Power Distribution Fault Cause Identification With Imbalanced Data Using the Data Mining-Based Fuzzy Classification E-Algorithm

Power distribution systems have been significantly affected by many outage-causing events. Good fault cause identification can help expedite the restoration procedure and improve the system reliability. However, the data imbalance issue in many real-world data sets often degrades the fault cause identification performance. In this paper, the E-algorithm, which is extended from the fuzzy classification algorithm by Ishibuchi to alleviate the effect of imbalanced data constitution, is applied to Duke Energy outage data for distribution fault cause identification. Three major outage causes (tree, animal, and lightning) are used as prototypes. The performance of E-algorithm on real-world imbalanced data is compared with artificial neural network. The results show that the E-algorithm can greatly improve the performance when the data are imbalanced     

分置式牛津型斯特林制冷机的数值分析与实验验证

对分置式牛津型斯特林制冷机进行了数值计算 ,介绍了计算模型考虑到的众多不可逆因素。通过对计算结果与实验结果的对比 ,验证了本文数值计算的准确性 ,说明本文计算模型与数值处理方法是切实可行的     

Mapping rule-based systems onto multicomputers using simulated annealing

In this paper, we present a static load balancing method for mapping production rules in an expert system onto processors of a message-passing multicomputer. The method uses simulated annealing to achieve a nearly optimal allocation of production rules onto processor nodes. The approach balances the initial rule distribution to avoid higher communication demand among processor nodes at run time. A formal mapping model is developed and a new cost function is defined for the annealing process. New heuristic swap functions and cooling policies are provided to ensure the quality of the annealing process. A software load balancing package, SIMAL, was implemented on a SUN workstation to carry out the benchmark experiments. The overhead associated with this mapping method is O(m In m), where m is the number of rules in the production system. Two benchmark production systems, Toru-waltz and Tourney, are mapped onto a hypercube computer with 32 nodes. Experimental benchmark results verify the effectiveness of the rule mapping method. The method can be applied for distributed artificial intelligence processing or for the parallel execution of cooperating expert systems on a message-passing multicomputer.     

Stabilization Methods for Spectral Element Computations of Incompressible Flows

A stabilization method for the spectral element computation of incompressible flow problems is investigated. It is based on a filtering procedure which consists in filtering the velocity field by a spectral vanishing Helmholtz-type operator at each time step. Relationship between this filtering procedure and SVV-stabilization method, introduced recently in [JCP, 2004, 196(2), p680], is established. A number of numerical examples are presented to show the accuracy and stabilization capability of the method.     

Fixed point theorem-based iterative learning control for LTV systems with input singularity

In this paper, we address a challenging and open problem: how to design a suitable iterative learning control (ILC) system in the presence of input singularity, which is incurred by the singularities of the system direct feed-through term. Considering two typical types of input singularities, we first revise the ILC operators accordingly by adding a forgetting factor and incorporating a time-varying learning gain, in the sequel guarantee ILC operators to be contractible. Next, using the Banach fixed-point theorem, we demonstrate that the output sequence can either enter and remains ultimately in a designated neighborhood of the target trajectory, or is bounded by a class K function. Finally, an illustrative example is presented.     

压电量测系统漏电影响分析

本文通过对压电量测系统等效电路图的逐步简化,得出矩形脉冲信号的漏电方程;并对系统在各种情况下的时间常数,漏电相对误差进行了计算,最后就系统在校准和现场测试中经常碰到的几种情况,进行了定量估算,从而解决了压电量测系统在使用中的一些具体问题。     

Effects of ACh on the electric activity of rostral ventrolateral medullary neurons of rat in vitro

Extracellular single-unit discharges were obtained from 165 spontaneously active neurons within the region of the rostral ventrolateral medulla (RVLM) by glass microelectrode from 89 brain slices of the Sprague-Dawley rats. The units could be divided into three types: regular (61.8%), irregular (24.2%) and silent (14%). Acetylcholine (ACh, 0.1, 0.3 mumol/L) showed four kinds of effects on spontaneous discharges of RVLM neurons: excitatory, inhibitory, biphasic and non-responsive, counting respectively 41.8%, 20%, 3% and 35.2% of the neurons tested. The excitatory effect of ACh was dose-dependent. The effects, either excitatory or inhibitory, of ACh (n = 49) were mostly blocked by atropine (0.3 mumol/L, n = 42). The excitatory effect of ACh (n = 14) could be blocked mainly by selective antagonist of M1 receptor, pirenzepine (PZ, 30 nmol/L, n = 9), but not by selective antagonist of M2 receptor, methoctramine (MT) and AFDX-116. The inhibitory effect of ACh (n = 10) could be blocked mostly by M2 receptor antagonist MT (30 nmol/L, n = 7); and this inhibitory effect (n = 9) could be blocked mostly by another M2 receptor antagonist AFDX-116 (30 nmol/L, n = 6), but not by M1 receptor antagonist PZ.     

八种新功能晶体的比热及其与相变掺杂物关系的实验研究

本文对八种新型功能晶体Ｌｉ２Ｂ４Ｏ７、Ｂｉ１２ＴｉＯ２０、Ｂｉ１２ＧｅＯ２０、Ｂｉ１２ＧｅＯ２０、Ｂｉ４Ｇｅ３Ｏ１２、Ｓｒ１－ｘＢａｘＮｂ２Ｏ６（ｘ＝０．３３，０．４８）、ＬｉＴａＯ３等在１３０～９７３Ｋ范围内的比热行为及其与相变、组分之间的关系进行了实验研究，给出了比热的多项式拟合方程，并与用纽曼－卡普定律及用Ｗｉｋｅｌｍａｎｎ经验方程的比热计算值作了对比，为晶体比热的估算提供了依据和方法。     

用于钻水平井的低密度水包油乳化钻井液

针对任平1井水平钻井的特点,研制了一种低密度、高油水比的水包油乳化钻井液。考察了乳化剂、增粘剂和配制工艺对乳状液性能的影响,评定了钻井液性能,介绍了现场应用情况。该钻井液性能稳定,润滑性好,净化井眼的能力强,能满足水平段钻井的要求。     

抗氧剂于有机PTC热敏导电材料性能的稳定作用研究

探讨了抗氧剂在聚乙烯 乙烯 醋酸乙烯酯共聚物 炭黑 (PE EVA CB)体系中的作用。结果表明 ,在体系中加入抗氧剂可以提高材料体系的结构稳定性 ,从而可以在一定程度上改善材料的热电稳定性。当在体系中加入 2 .0 %(w)的抗氧剂时可收到良好效果。