A multi-start central force optimization for global optimization

Central force optimization (CFO) is an efficient and powerful population-based intelligence algorithm for optimization problems. CFO is deterministic in nature, unlike the most widely used metaheuristics. CFO, however, is not completely free from the problems of premature convergence. One way to overcome local optimality is to utilize the multi-start strategy. By combining the respective advantages of CFO and the multi-start strategy, a multi-start central force optimization (MCFO) algorithm is proposed in this paper. The performance of the MCFO approach is evaluated on a comprehensive set of benchmark functions. The experimental results demonstrate that MCFO not only saves the computational cost, but also performs better than some state-of-the-art CFO algorithms. MCFO is also compared with representative evolutionary algorithms. The results show that MCFO is highly competitive, achieving promising performance.     

基于康复训练中力信号的人体参与度建模

设计一种基于人机接触力的人体主动参与程度评估模型,用于康复机器人应用中的主动康复训练。通过人体的肌电信号得到肌肉活跃度,确定肌电信号与人体参与度的关系。分析这一过程中人机接触力的变化,将腿部力信号平均值以及腰部力信号方差作为模型输入,对基于肌电信号的参与度模型进行拟合,得到基于力信号的参与度模型,使用肌电信号参与度模型对力信号参与度模型进行验证,证明了该模型的有效性。该方法避免了肌电信号采集时干扰较大且准备工作繁琐等缺点,具有良好的实用性。     

基于量子效应的微型推进器设计

微/纳机电系统(MEMS/NEMS)技术的发展,大大促进了航空航天领域飞行器的微型化。依据量子理论,有效提取真空中的零点能,并以此作为驱动能源,可以解决微型飞行器由于必须携带燃料而增加重量等问题。从理论上阐述了真空零点能及Casimir力的产生机理,研究了真空中两平行平板和矩形腔等结构设计依据,提出并建立了以Casimir力作为驱动力的微型推进器设计模型。     

对挑梁埋置砌体部分内力计算的探讨

根据前苏联M.N.高尔波诺夫-波沙道夫的<弹性地基上结构物的计算>[1]方法,结合工程设计实例,对钢筋混凝土挑梁埋置砌体部分的内力计算进行了探讨.通过对工程设计实例的分析,给工程设计人员提供了在设计中遇到类似构件时较为实用的一种精确计算方法,避免粗略计算挑梁时易造成事故隐患的缺陷.     

WAVE INTERACTION WITH PERFORATED CAISSON BREAKWATERS

The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data.     

Topology optimization of trusses using genetic algorithm,force method and graph theory

In this article size/topology optimization of trusses is performed using a genetic algorithm (GA), the force method and some concepts of graph theory. One of the main difficulties with optimization with a GA is that the parameters involved are not completely known and the number of operations needed is often quite high. Application of some concepts of the force method, together with theory of graphs, make the generation of a suitable initial population well‐matched with critical paths for the transformation of internal forces feasible. In the process of optimization generated topologically unstable trusses are identified without any matrix manipulation and highly penalized. Identifying a suitable range for the cross‐section of each member for the ground structure in the list of profiles, the length of the substrings representing the cross‐sectional design variables are reduced. Using a contraction algorithm, the length of the strings is further reduced and a GA is performed in a smaller domain of design space. The above process is accompanied by efficient methods for selection, and by using a suitable penalty function in order to reduce the number of numerical operations and to increase the speed of the optimization toward a global optimum. The efficiency of the present method is illustrated using some examples, and compared to those of previous studies. Copyright © 2003 John Wiley & Sons, Ltd.     

厚膜永磁阵列微致动器的磁路研究

研究了厚膜永磁阵列微致动器中的磁场分布，并研究了永磁阵列单元几何尺寸对微致动器电磁力的影响。结果表明，厚膜永磁阵列单元高宽比和磁体单元间隔对微致动器电磁力影响较大磁徕单元高宽比为0．7是一个比较合适的尺寸。     

多晶硅衬底上的RF MEMS开关

在微机械开关与硅IC工艺设计和兼容方面进行了改进,获得了一种可与IC工艺兼容的RFMEMS微机械开关.采用介质隔离工艺技术把这种RFMEMS微机械开关制作在绝缘的多晶硅衬底上,实现了与IC工艺兼容;采用在金属膜桥的端点附近刻蚀一些孔的优化方法,降低了RFMEMS微机械开关的下拉电压.用TE2 819电容测试设备测试开关的电容,测得开关的开态电容、关态电容和致动电压分别为0 32 pF、6 pF和2 5V .用HP875 3C网络分析仪对RFMEMS微机械开关进行了RF特性测试,得出RFMEMS微机械开关在频率1 5GHz下关态的隔离度为35dB ,开态的插入损耗为2dB ,用示波器测得该开关的开关     

镍铬合金在酸性CuCl2溶液中反应机理

对铜在酸性CuCl_2溶液中蚀刻反应机理论述,利用氧化-还原电动势原理,详细论述了Ni80Cr20合金在酸性CuCl_2溶液中化学蚀刻反应机理,以及影响蚀刻速度的因素,并对溶液中金属离子的存在形式作了验证。     

600 A IGBT开关电路及其散热系统设计

采用IGBT开关电路，对大功率电阻带进行直流脉宽调制控制，实现了内燃机车大功率直流发电机负载实验中的负载大小的连续调节。为了避免在实验过程中IGBT器件的温度过高，采用独特的双管IGBT结构和双向强迫风冷的散热系统。实验表明该电路运行稳定、可靠。