Nonsmooth identification of mechanical systems with backlash-like hysteresis

Backlash-like hysteresis is one of the nonsmooth and multi-valued nonlinearities usually existing in mechanical systems. The traditional identification method is quite difficult to be used to model the systems involved with such complex nonlinearities. In this paper, a nonsmooth recursive identification algorithm for the systems with backlash-like hysteresis is proposed. In this method, the concept of Clarke subgradient is introduced to approximate the gradients at nonsmooth points and the so-called bundle method is used to obtain the optimization search direction in nonsmooth cases. Then, a recursive algorithm based on the idea of bundle method is developed for parameter estimation. After that, the convergence analysis of the algorithm is investigated. Finally, simulation results to validate the proposed method on a simulated mechanical transmission system are presented.     

漏电保护器投运难题的解决方案

分析剩余电流动作保护装置的常见故障,编制常见故障排查口袋书,采取简单易懂、能按图索骥的快速查找方法,破解剩余电流动作保护装置投运难题.     

A novel artificial bee colony algorithm with Powell's method

Artificial bee colony (ABC) algorithm is a relatively new optimization technique which has been shown to be competitive to other population-based algorithms. However, there is still an insufficiency in ABC regarding its solution search equation, which is good at exploration but poor at exploitation. To address this concerning issue, we first propose a modified search equation which is applied to generate a candidate solution in the onlookers phase to improve the search ability of ABC. Further, we use the Powell's method as a local search tool to enhance the exploitation of the algorithm. The new algorithm is tested on 22 unconstrained benchmark functions and 13 constrained benchmark functions, and are compared with some other ABCs and several state-of-the-art algorithms. The comparisons show that the proposed algorithm offers the highest solution quality, fastest global convergence, and strongest robustness among all the contenders on almost all test functions.     

漳河水库入库径流序列变化趋势分析

依据漳河水库1963-2008年入库径流资料,采用R/S分析方法和M ann-Kendall参数秩次相关检验法对其未来入库径流变化趋势进行了分析。结果表明:①水库流域未来径流量将呈缓慢下降的趋势,且未来1月和7月的径流量变化趋势的随机性成份可能很大,应采取必要对策和措施,以应对未来可能出现的干旱或暴雨洪涝等自然灾害。②1995年为突变点,前后两个系列的统计特征值均具有明显的差异,已经不符合"一致性"的要求。③对于20世纪70~80年代的持续枯水期,应理解为这只是其径流丰枯周期变化中的一个枯水期。④流域人类活动日趋频繁,使得流域下垫面条件发生了较大的变化,对入库径流量有较大的影响。     

浅谈计算机硬盘数据丢失原因及恢复

本文主要对计算机硬盘数据丢失的原因、恢复软件的应用方法进行分析。     

ALOF——新一代三维疲劳裂纹扩展分析软件

针对当前亟需开发能分析和评估含缺陷工程结构及装备的专业商业软件的现况,基于成熟的扩展有限元法(eXtended Finite Element Method,XFEM)和自主研发的虚节点法(Virtual Node Method,VNM),推出具有完全自主知识产权的三维疲劳裂纹扩展分析软件ALOF(Analyses Laboratory of Fracture).介绍ALOF求解断裂问题的流程及其特点:可以方便地导入完整的CAD模型及多种形式的裂纹模型,可以自动生成疏密合理的二维和三维裂纹扩展分析网格;具有丰富的失效准则库;能自动分层加密裂尖区域网格;能全自动地进行裂纹扩展计算等.与同类软件相比,ALOF更简单、更精准、更高效和更专业.利用ALOF进行的3个实际工程案例表明,ALOF能准确、高效评估任意复杂缺陷体的剩余强度和疲劳寿命.     

项目教学法在开放教育《VB程序设计》辅导中的应用

开放教育教学辅导中“项目教学法”,就是精心设计辅导项目、传授规范知识、优化教学过程和注重操作技能的培养     

运输车辆安全体系评价的研究

该文通过对车辆安全因数的分析、得出子危险集。在分析评价方法特征技术上应用了选用模糊推理模型(FIS)的评价方法对车辆的危险度进行评价与仿真,其结果是可信的。实现了对车辆安全进行量态和动态的评价体系。     

从应用的角度评估MAS体系结构风格

近年来,Agent技术已成为开发复杂系统的一项可行技术,但对MAS体系结构的研究仍然面临着一定的挑战。本文从已有的MAS体系结构风格和开发框架出发,对MAS体系结构风格进行了分析、提取和归类,从应用角度提出了一个评估MAS体系结构风格的框架,并通过两个案例说明了如何利用评估结果为具体应用选择合适的风格。     

应用原对偶方法光滑向量的四阶算子分裂方法

高阶算子分裂方法在改善图像边缘阶梯化、提高计算效率等问题上有很好的作用,其主要思想是将四阶的偏微分方程分裂成两个二阶的偏微分方程分别求解,先进行向量光滑,然后再进行图像重构。相对于第一步的一般显式数值迭代方法,本文应用原对偶格式进行变量替换,应用拟牛顿进行向量光滑。数值结果表明,该方法很好地提高了信噪比,且视觉效果显著。