Multi-innovation stochastic gradient algorithm for multiple-input single-output systems using the auxiliary model

In order to reduce computational burden and improve the convergence rate of identification algorithms, an auxiliary model based multi-innovation stochastic gradient (AM-MISG) algorithm is derived for the multiple-input single-output systems by means of the auxiliary model identification idea and multi-innovation identification theory. The basic idea is to replace the unknown outputs of the fictitious subsystems in the information vector with the outputs of the auxiliary models and to present an auxiliary model based stochastic gradient algorithm, and then to derive the AM-MISG algorithm by expanding the scalar innovation to innovation vector and introducing the innovation length. The simulation example shows that the proposed algorithms work quite well.     

Improvements in Residual Stress Measurement by the Incremental Centre Hole Drilling Technique

This paper presents results which advance and improve the usefulness, accuracy and efficiency of incremental centre hole drilling as a method of measuring near surface residual stress fields. Particular emphasis is placed on providing optimal values for the number of drilling step increments to be used and their corresponding size. Guidelines on the optimal values for the number and size of steps to use during measurements are presented for various ratios of hole radius to strain gauge rosette radius in the form of tabulated data. These guidelines are subsequently incorporated into a new data analysis program which permits very near surface residual stress fields to be accurately determined in real components. The benefits of the new approach are highlighted by reporting the results of measurements made on three industrial components, each of which has been subjected to a well-known engineering process. These components are a shot-peened spring-steel, a friction stir welded aluminium alloy, and a titanium alloy subjected to three different machining processes. The results reveal that the improvements to the incremental centre hole drilling technique can provide measured residual stresses from depths ranging from about 10 m to 1 mm.     

变频调速系统中电机主回路电流的检测处理和保护

本文给出了一种三相异步电动机变频调速电源中电机主回路电流的采样,信号处理,以及状态输出的实用电路。     

半夏人工种子的研究

以半夏株芽生长的茎尖作外植体诱导小块茎,筛选直５ｍｍ的小块芭是作人工种子。     

GS-DFB半导体激光器的优化设计

对ＧＳＤＦＢ半导体激光器的参数进行了优化设计。采用脉冲峰值功率、脉宽、谱宽、脉宽谱宽积以及峰值功率与脉宽谱宽积之比等参数来综合描述激光器输出脉冲特性,研究了这些参数随偏置电流、调制电流等外部参数的变化,并找出了相应的优化值。     

输出反馈网络控制系统的稳定性

针对具有输出反馈的网络控制系统，研究了基于模型参考控制器的网络控制系统稳定的条件，提出了一种利用被控对象的信息设计系统参考模型，从而降低网络传输的数据量，以适应网络传输需求的控制方法。文章给出并证明了在这种输出反馈控制条件下，网络控制系统稳定时所应满足的充分必要条件。通过Matlab对典型控制对象进行了仿真实验，表明了该结论的正确性和有效性。     

基于改进IMK恢复力模型的填充墙RC框架结构地震易损性分析

为了对填充墙RC框架结构在设防大震下的抗震能力进行评估,采用OpenSees有限元软件,建立了填充墙RC框架结构的数值模型,其中,梁柱构件采用基于改进IMK恢复力模型的集中塑性铰单元进行建模,填充墙用双对角斜撑受压杆模拟,并采用基于Clough模型的桁架单元建模。以填充墙的不同布置方式作为参数,设计了4种模型,对模型进行了44条地震波下的增量动力时程分析和倒塌易损性分析。结果表明,底层不布置填充墙的模型和底部两层各有一跨布置填充墙的模型不满足我国规范中"大震不倒"的性能要求,在实际工程中应尽量避免运用此类型的框架结构,需要对已有的此类结构进行加固处理。     

用场分析法求解速调管输出回路特性参数

 为解决速调管输出回路特性参数计算时遇到的困难,结合场分析的手段和3维电磁场模拟计算软件ISFEL3D后处理部分,提出了场分析法。理论分析表明,场分析法可用于计算单注单间隙、多注单间隙、单注多间隙和多注多间隙等各种速调管输出回路的谐振频率、间隙阻抗实部和外观品质因数等特性参数。通过对单注单间隙速调管输出回路的举例计算表明,场分析法的计算结果与反射相位法和等效间隙阻抗法的计算结果吻合较好,初步证实了该方法的可操作性和理论推导的正确性。     

基于WSN的战场声目标多特征联合智能分类识别

本文利用WSN对战场声目标进行分类识别。由于战场上目标的声音信号构成非常复杂,采用单一特征很难全面反映其特点,提取多种特征来构成联合特征向量显得非常重要。然而简单的多特征联合识别,给识别带来维数灾难。本文提出,首先对滤波后的信号进行功率谱特征提取,再利用KPCA进行降维处理,将处理后的特征向量与最优小波包能量提取的特征向量组合,最后利用支持向量机完成对战场五类声目标的识别。仿真实验表明,采用这种方法能有效地提高分类识别的准确度。