Optimized PI+ load–frequency controller using BWNN approach for an interconnected reheat power system with RFB and hydrogen electrolyser units

This paper investigates a renewable energy resource’s application to the Load–Frequency Control of interconnected power system. The Proportional-Integral (PI) controllers are replaced with Proportional-Integral Plus (PI+) controllers in a two area interconnected thermal power system without/with the fast acting energy storage devices and are designed based on Control Performance Standards (CPS) using conventional/Beta Wavelet Neural Network (BWNN) approaches. The energy storing devices Hydrogen generative Aqua Electroliser (HAE) with Fuel cell and Redox Flow Battery (RFB) are incorporated to the two area interconnected thermal power system to efficiently damp out the electromechanical oscillations in the power system because of their inherent efficient storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirements. The system was simulated and the frequency deviations in area 1 and area 2 and tie-line power deviations for 5% step- load disturbance in area 1 are obtained. The comparison of frequency deviations and tie-line power deviations of the two area interconnected thermal power system with HAE and RFB designed with BWNN controller reveals that the PI+ controller designed using BWNN approach is found to be superior than that of output response obtained using PI+ controller. Moreover the BWNN based PI+ controller exhibits a better transient and steady state response for the interconnected power system with Hydrogen generative Aqua Electroliser (AE) unit than that of the system with Redox Flow Battery (RFB) unit.     

CCD型束流截面探测器

CCD型束流截面探测器的主要特点是使用电荷耦合器件做传感器,用束流同步光中的可见光成份做为信号源。该探测器同时具有模拟量和数字量两种输出,工作周期短,速度高,不影响束团粒子寿命,在电子储存环物理运行中,是一种有效的探测设备。     

电子和β射线两用外推电离室的研制

本文研制了一台测量电子束和β射线吸收剂量的外推电离室,其空腔室壁材料可拆换并分别与空气、组织和硅等效,收集电极名义直径为1.5、3、10和30mm,空气空腔可变范围为0.2～15mm。该外推电离室具有在空腔内部测温,自动改变窗口上方材料厚度及采用微型计算机控制等特点。适用于测10 MeV能量以下,剂量率为10~5～10~(-3)Gy/h的电子或β射线吸收剂量。整个外推电离室自动测剂量系统在测~(204)TLβ放射源表面剂量率的不确定度为2.3％。测1.5 MeV电子束在硅和哈密瓜深部剂量率时,不确定度分别为4.0％和2.8％。     

Noble-free potassium-bimetallic catalysts supported on beta-zeolite for the simultaneous removal of NOx and soot from simulated diesel exhaust

This paper deals with the activity of the KCu and KCo catalysts supported on beta-zeolite for the simultaneous NO_x/soot removal from a simulated diesel exhaust, containing C₃H₆ as model hydrocarbon. In order to reveal the effect of potassium, the corresponding monometallic catalysts (Co/beta and Cu/beta) were analyzed and different potassium loadings were used. In addition, for comparative purpose, the performance of a platinum based catalyst (Pt/beta) was studied. All noble-free catalysts show, at 450 °C, a high activity for the simultaneous NO_x/soot removal. Among them, K1Cu/beta presents the best global performance at 350 and 450 °C achieving a high soot consumption rate (comparable to platinum catalysts) and the highest NO_x reduction. In contrast to platinum catalysts, K1Cu/beta has the advantage that the main reaction products are N₂ and CO_2.     

基于 Beta信誉系统的无线传感网络鲁棒安全自定位

针对现实应用中各种不利因素干扰而严重影响无线传感网络的定位性能的问题,提出一种鲁棒安全定位算法. 首先在Beta信誉系统的基础上建立信任评估框架;然后,传感器节点在多跳通信范围内将锚节点的最终信任值与所存储的阈值进行比较;最后,采用基于泰勒级数展开的加权最小二乘法估算普通传感器节点的坐标. 仿真结果验证了该算法的有效性和鲁棒性,相比其他几种定位算法,该算法具有更高的定位精度,不仅能够很好地识别出无线传感网络中的恶意锚节点,同时大大地提高了节点自定位技术的定位精度.     

Medical image contrast enhancement based on improved sparrow search algorithm

The collection or transmission of medical images is often disturbed by various factors, such as insufficient brightness and noise pollution, which will result in the deterioration of image quality and significantly affect the clinical diagnosis. To improve the quality of medical images, a contrast enhancement method based on improved sparrow search algorithm is proposed in this paper. The method is divided into two steps to enhance the medical images. First, a new transform function is introduced to improve the brightness or contrast of medical images, and two parameters in the transform function are optimized by the improved sparrow search algorithm. Second, adaptive histogram equalization method with contrast limited is used to equalize the result image of the previous step to make the pixel distribution of the image more uniform. Finally, a large number of experiments and qualitative and quantitative analyses were conducted on the common data sets. The analysis results demonstrate that the presented approach outperforms some existing medical image processing approaches.     

基于正态信息扩散原理的路基沉降模糊可靠度分析

基于正态信息理论,给出了路基沉降概率分布的拟合方法,并利用精度较高K-S检验法验证了该方法的正确性。将Beta分布引入路基沉降模糊失效事件的隶属函数中,解决了常用隶属函数存在的不足。同时,利用模糊可靠度理论,给出了路基沉降模糊可靠度的计算公式。最后通过工程实例验证了本文方法的有效性。     

Evaluation and comparison of estimation methods for failure rates and probabilities

An updated parametric robust empirical Bayes (PREB) estimation methodology is presented as an alternative to several two-stage Bayesian methods used to assimilate failure data from multiple units or plants. PREB is based on prior-moment matching and avoids multi-dimensional numerical integrations. The PREB method is presented for failure-truncated and time-truncated data. Erlangian and Poisson likelihoods with gamma prior are used for failure rate estimation, and Binomial data with beta prior are used for failure probability per demand estimation. Combined models and assessment uncertainties are accounted for. One objective is to compare several methods with numerical examples and show that PREB works as well if not better than the alternative more complex methods, especially in demanding problems of small samples, identical data and zero failures. False claims and misconceptions are straightened out, and practical applications in risk studies are presented.     

The beta exponential distribution

The exponential distribution is perhaps the most widely applied statistical distribution for problems in reliability. In this note, we introduce a generalization—referred to as the beta exponential distribution—generated from the logit of a beta random variable. We provide a comprehensive treatment of the mathematical properties of the beta exponential distribution. We derive expressions for the moment generating function, characteristic function, the first four moments, variance, skewness, kurtosis, mean deviation about the mean, mean deviation about the median, Rényi entropy, Shannon entropy, the distribution of sums and ratios, and the asymptotic distribution of the extreme order statistics. We also discuss simulation issues, estimation by the methods of moments and maximum likelihood and provide an expression for the Fisher information matrix. We hope that this generalization will attract wider applicability in reliability.