户内金属铠装移开式高压开关柜非典型故障分析与处理

本文阐述了KYN28-12型高压开关柜的结构组成和主要功能,并对开关在运行过程中所遇到的几种非典型故障的原因进行了分析判断,介绍了故障的处理方法和今后维护中的注意事项.     

组合导体目标电磁特性的快速多极算法计算

用快速多极算法分析具有任意线、面、体组合的电大尺寸理想导体目标的电磁散射和辐射特性.统一采用RWG基函数对线、面、体导体上的电流进行展开;使用了新的设置基函数和未知量的方法来处理任意的线-面,面-面连接问题;并使用多层快速多极算法结合ILUT预处理算法加速求解过程.数值结果验证了本文方法的准确性和高效性.     

两千瓦CO2激光热处理研究

本文叙述了采用两千瓦级CO2激光器对铬钼镍合金铸铁、球墨铸铁及激冷铸铁等几种材料进行激光表面处理的实验研究和结果.探讨了处理前的预处理、不同的功率密度、扫描速度及光斑尺寸对激光硬化的影响.对采用相变硬化和熔化-凝固硬化的激光处理前后的金相组织的特点,进行了对比和分析.此外.对激冷铸铁在激光处理时产生的裂纹作了初步的探讨.     

无源多基地雷达中一种综合航迹处理方法

本文对基于调频广播信号的无源多基地雷达系统中的目标跟踪问题进行了研究,提出了一种综合航迹处理方法.本文将航迹划分为四种状态,即起始航迹,试验航迹,确认航迹,以及消亡航迹,详细介绍了每一种航迹的处理方式.本文顺序地利用每个接收-发射对的观测量来更新航迹,以减小算法复杂度.仿真实验与实测数据结果证明了本文算法的有效性.     

灰色-马尔可夫链模型在电信业务预测中的应用

大数据时代的到来,数据挖掘与分析已经变得越来越重要.如何高效准确的分析和利用电信业务量中的各种参数,通过数据的准确分析与预测调整公司战略目标与指导生产,已经成为每一位通信人迫切需要解决的问题.本文通过对灰色-马尔可夫链模型的分析,提出了在电信业务数据分析预测中使用灰色-马尔可夫链模型对数据进行建模处理的方法.     

基于特征分解的高频地波雷达电离层杂波抑制

针对高频地波雷达中的电离层杂波,利用特征分解法在阵元-脉冲域和脉冲-距离域对它进行联合处理,并对特征分解法在脉冲-距离域和阵元-脉冲域分别进行了如下改进:在脉冲-距离域采用循环重构数据协方差矩阵,而在阵元-脉冲域则按扫频周期分段正交分解.OSMAR2003系统的实测数据表明:这种处理方法对抑制电离层杂波是有效的.     

高频声表面波振荡器

本文就250兆赫SAWO的有关问题提出了一些看法.根据SAWO频谱特性提出了对频控元件(窄带延迟线)和电路的要求,对延迟线Q值、结构以及基波与谐波工作、电路选择以及有关应用中的处理、振荡器自激等问题进行一些探讨.本文还介绍了一种利用SAWO中谐波分量来获得高频SAWO的方法.通过实验得到了频率为300兆赫,瞬态特性为10~(-9)/秒,常温下稳定性为10~(-6)/天的振荡器样品.对电路的非线性效应进行了分析,并对它的频率稳定性和频谱特性提出了初步看法.     

卷积计算的数据并行实现方法

基于局部线性滤波函数的大多数图像处理操作,都可以表示成图像数据与一个权值样板的卷积.对于N×N的图像和M×M(M＜N)的模板,卷积算法在单处理机上用传统的方法实现需要O(N2M2)时间.显然它应当采用数据并行的处理方法来实现.本文较详细地讨论了卷积算法在局部寄存器个数受限与不受限情况下的两维处理元阵列的数据并行实现方法,提出了一种适用于具有有限局部寄存器的-维处理元阵列的卷积并行算法,并对算法的复杂度进行了分析.     

Cd_(1-x)Zn_xTe(x=0.04)表面处理的低温拉曼散射和电学特性研究

测量了几种不同处理的 Cd1 - x Znx Te(x=0 .0 4)表面的傅里叶变换拉曼散射光谱和电流 -电压 (I- V)特性 .通过分析拉曼光谱反 Stokes分量 ,并与表面 I- V特性进行比较 ,结果表明与表面处理相联系的晶格声子的行为反映了表面完整性的变化 ,Te沉淀是影响表面质量的关键因素 ,并对有关表面处理方法的实际应用进行了讨论 .     

电子散斑相位检测的滤波方法研究

本文提出空域中值迭代滤波方法和频域离散余弦变换滤波方法,利用三步相移技术成功实现相位检测.对两种方法所得结果进行了比较.实验结果表明这两种方法对ESPI条纹图像进行处理是有效的.     

高频雷达海杂波的多重分形建模方法研究

将多重分形理论引入高频雷达海杂波建模,提出了一种新的高频雷达海杂波的时域多重分形模型。对比分析了实测数据海杂波、分数布朗运动(FBM)模型和多重分形模型的质量指数函数和奇异指数,结果表明:该多重分形模型与实测数据具有相似的多重分形性。此外,通过对韦布尔分布、对数正态分布和瑞利分布三种最常用海杂波的概率密度函数的比较分析,并利用修正的柯尔莫哥洛夫-斯米尔洛夫(K-S)统计检验,得出了高频雷达海杂波的多重分形模型具有先验的统计特性的结论,从而进一步证明了该多重分形模型的合理性和有效性。     

GPS与惯性导航系统融合的精确连续定位算法

为了克服独立的惯性导航系统无限制的位置误差和 Ｇ Ｐ Ｓ的１ Ｈｚ 慢速数据修正速率的缺陷,本文提出了对两种具有不同输出数据速率运动传感器 Ｇ Ｐ Ｓ与 Ｉ Ｎ Ｓ融合算法,研究了五点二次和两点线性预测的高精度连续融合定位算法,真实 Ｇ Ｐ Ｓ数据和模拟 Ｉ Ｎ Ｓ数据融合的实验证明了该方法的正确性,为在中、高动态环境下的高精度实时连续定位提供了一种新的途径。     

用于步进频连续波雷达旁瓣抑制的自适应CLEAN技术

为了解决步进频连续波雷达中的强目标距离旁瓣掩盖弱小目标问题,对步进频自适应脉压算法( SFCW-RMSMIL)进行修正,并联合修正SFCW-RMSMIL算法和CLEAN技术,提出了一种新的自适应CLEAN算法( A-CLEAN)。该算法解决了弱小目标能量严重压制问题,同时还能精确估计各目标的幅度和位置,提高了雷达对弱小目标的检测能力。最后利用仿真数据、实测数据以及蒙特卡洛实验验证了新提出的A-CLEAN算法的有效性和实用性。     

The use of the SPSA method in ECG analysis

The classification, monitoring, and compression of electrocardiogram (ECG) signals recorded of a single patient over a relatively long period of time is considered. The particular application we have in mind is high-resolution ECG analysis, such as late potential analysis, morphology changes in QRS during arrythmias, T-wave alternants, or the study of drug effects on ventricular activation. We propose to apply a modification of a classical method of cluster analysis or vector quantization. The novelty of our approach is that we use a new distortion measure to quantify the distance of two ECG cycles, and the class-distortion measure is defined using a min-max criterion. The new class-distortion-measure is much more sensitive to outliers than the usual distortion measures using average-distance. The price of this practical advantage is that computational complexity is significantly increased. The resulting nonsmooth optimization problem is solved by an adapted version of the simultaneous perturbation stochastic approximation (SPSA) method of. The main idea is to generate a smooth approximation by a randomization procedure. The viability of the method is demonstrated on both simulated and real data. An experimental comparison with the widely used correlation method is given on real data.     

TOA Estimation Technique for IR‐UWB Based on Homogeneity Test

This paper deals with the estimation of the time of arrival (TOA) of ultra‐wideband signals under IEEE 802.15.4a channel models. The proposed approach is based on a randomness test and consists of determining whether an autoregressive (AR) process modeling an energy frame is random or not by using a distance to measure the randomness. The proposed method uses a threshold that is derived analytically according to a preset false alarm probability. To highlight the effectiveness of the developed approach, simulation setups as well as real data experiments are conducted to assess the performance of the new TOA estimation algorithm. Thereby, the proposed method is compared with the cell averaging constant false alarm rate technique, the threshold comparison algorithm, and the technique based on maximum energy selection with search back. The obtained results are promising, considering both simulations and collected real‐life data.     

基于改进局部切空间排列的流形学习算法

局部切空间排列是一种广受关注的流形学习算法,其具备实现简单、全局最优等特点,但其难以有效处理稀疏采样或非均匀分布的高维观测数据。针对这一问题,该文提出一种改进的局部切空间排列算法。首先,提出一种基于L1范数的局部切空间估计方法,由于同时考虑了距离和结构因素,该方法得到的切空间较主成分分析方法更为准确。其次,在坐标排列步骤为了减小排列误差,设计了一种基于流形结构的加权坐标排列方案,并给出了具体的求解方法。基于人造数据和真实数据的实验表明,该算法能够有效地处理稀疏和非均匀分布的流形数据。     

Method of determining the admittance loading of slot coupled T-junctions

A new method is presented for inferring the real and imaginary parts of admittance loading seen by the exciting guide of an H-plane slot coupled T-junction from measurement of the magnitudes of the reflection and coupling coefficients. These quantities are measured using an HP network analyser together with a reflection and transmission test unit, which provides better accuracy of measurement. A comparison between measured data with the theoretical values determined by the authors is presented.     

Comparative analysis of master-slave latches and flip-flops forhigh-performance and low-power systems

In this paper, we propose a set of rules for consistent estimation of the real performance and power features of the flip-flop and master-slave latch structures. A new simulation and optimization approach is presented, targeting both high-performance and power budget issues. The analysis approach reveals the sources of performance and power-consumption bottlenecks in different design styles. Certain misleading parameters have been properly modified and weighted to reflect the real properties of the compared structures. Furthermore, the results of the comparison of representative master-slave latches and flip-flops illustrate the advantages of our approach and the suitability of different design styles for high-performance and low-power applications     

New methods for dynamic mosaicking

This paper presents a new technique for the creation of a sequence of mosaic images from an original video shot. A mosaic image represents, on a single image, the scene background seen all over the sequence and its creation requires the estimation of the warping parameters and the use of a blending technique. The warping parameters permit one to represent each original image in the mosaic reference. An estimation method, based on a direct comparison between the current original image and the previously calculated mosaic is proposed. A new analytic minimization criterion is also designed to optimize the determination of the blending coefficient used for the update of the mosaic image with a new original image. This criterion is based on constraints related to the temporal variations of the background, the temporal delay and the resolution of the created mosaic images, while its minimization can be analytically performed. Finally, the proposed method is applied to the creation of new video sequences in which the camera point of view, the camera focal, or the image size are modified. This approach has been tested and validated on real video sequences with large camera motion.     

Classification of sets of mixed pixels with the hypothesis-testingHough transform

A new method is presented for mixed pixel classification where the classification of groups of mixed pixels is achieved by using the hypothesis-testing Hough transform. The motivation of the work is that some other estimation methods based on robust statistics, such as the standard Hough transform, have been criticised that, although they can cope with the presence of outliers, they give poor performance in the absence of outliers in comparison to the least-squares-error method. The method proposed in the paper is demonstrated using simulated data and proved to perform equally well in the presence and in the absence of outliers. It is also applied to real Landsat TM data