Improved nonlinear trajectory tracking using RBFNN for a robotic helicopter

This paper presents a backstepping control method using radial‐basis‐function neural network (RBFNN) for improving trajectory tracking performance of a robotic helicopter. Many well‐known nonlinear controllers for robotic helicopters have been constructed based on the approximate dynamic model in which the coupling effect is neglected; their qualitative behavior must be further analyzed to ensure that the unmodeled dynamics do not destroy the stability of the closed‐loop system. In order to improve the controller design process, the proposed controller is developed based on the complete dynamic model of robotic helicopters by using an RBFNN function approximation to the neglected dynamic uncertainties, and then proving that all the trajectory tracking error variables are globally ultimately bounded and converge to a neighborhood of the origin. The merits of the proposal controller are exemplified by four numerical simulations, showing that the proposed controller outperforms a well‐known controller in (J. Robust Nonlinear Control 2004; 14 (12):1035–1059). Copyright © 2009 John Wiley & Sons, Ltd.     

Delay-dependent Non-fragile H∞ Filtering for Uncertain Fuzzy Systems Based on a Switching Fuzzy Model and Piecewise Lyapunov Function

This paper is concerned with the non-fragile H∞ filter design problem for uncertain discrete-time Takagi-Sugeno (T-S) fuzzy systems with time delay. To begin with, the T-S fuzzy system is transformed to an equivalent switching fuzzy system. Then, based on the piecewise Lyapunov function and matrix decoupling technique, a new delay-dependent non-fragile H∞ filtering method is proposed for the switching fuzzy system. The proposed condition is less conservative than the previous results. Since only a set of LMIs is involved, the filter parameters can be solved directly. Finally, a design example is provided to illustrate the validity of the proposed method.     

The structure of canalizing functions

The structure of a canalizing function is discussed. Using a new matrix product, namely semitensor product, the logical function is expressed in its matrix form. From its matrix expression, a criterion is obtained to test whether a logical function is a canalizing function. Then a formula is obtained to calculate the number of canalizing functions. Moreover, an algorithm is presented to generate canalizing functions. Finally, some results obtained are extended to seminested canalizing functions.     

A self-adaptive linear evolutionary algorithm for solving constrained optimization problems

In many real-world applications of evolutionary algorithms, the fitness of an individual requires a quantitative measure. This paper proposes a self-adaptive linear evolutionary algorithm (ALEA) in which we introduce a novel strategy for evaluating individual’s relative strengths and weaknesses. Based on this strategy, searching space of constrained optimization problems with high dimensions for design variables is compressed into two-dimensional performance space in which it is possible to quickly identify ‘good’ individuals of the performance for a multiobjective optimization application, regardless of original space complexity. This is considered as our main contribution. In addition, the proposed new evolutionary algorithm combines two basic operators with modification in reproduction phase, namely, crossover and mutation. Simulation results over a comprehensive set of benchmark functions show that the proposed strategy is feasible and effective, and provides good performance in terms of uniformity and diversity of solutions.     

浅析功能美在室内装饰设计中的应用

本文就功能美的角度,对其在室内装饰设计中的应用展开论述。我们可以了解到,室内装饰设计是使室内环境能形成一个统一体,即其功能美与形式美的协调统一,是设计成功与否的关键所在。本文主要就功能美的一系列因素进行阐述,并结合国外的设计图片实例,探讨功能美的作用。     

中国民间游戏和电子游戏的社会功能差异

游戏是一种古老的社会文化现象,自从有了人类就有了游戏。随着人类社会的发展、经济和科技水平的不断上升,游戏的概念和内涵也不再是跳皮筋、踢毽子等民间游戏活动。一种承载着更多经济、科技和文化内涵的游戏行为——电子游戏正在渗透到人们的生活中,人们认识到它更多的社会功能和价值,这种社会功能和价值因为游戏的内容、形式以及物质载体的巨大变化而形成了民间游戏和电子游戏的很大差异。     

浅析建筑色彩的影响因素

建筑色彩不但具有装饰作用,更具有表达设计师理念、弥补造型缺陷,强化形体等作用,越来越受到建筑设计师的重视。而建筑色彩是经过了漫长的时间才发展成为一门独立的科学,在发展过程中影响建筑色彩的因素有很多种。了解和认识这些影响因素,才能在建筑设计才能更好的利用色彩为建筑加分。     

基于GA的多路径测试数据生成器适配函数设计

提出了基于GA的多路径测试数据生成的概念和实现方法。讨论了为了实现多路径测试数据生成,设计有效的和高效的适配函数应考虑的因素,用实际案例针对提出的适配函数进行了功能性能验证。结果表明了适配函数设计的有效性。     

一种基于核密度估计的模拟电路故障诊断方法

为解决模拟电路中含有噪声等异常信息给支持向量机的最优分类面建立带来的困难,提出了一种基于核密度估计方法的模拟电路故障诊断新方法。首先提取电路的时域信号统计参数作为故障特征,然后运用核密度估计方法构造模糊隶属度函数,将该隶属度函数应用到模糊支持向量机上进行故障诊断。通过训练模糊支持向量机获得故障诊断模型,实现对电路单故障和多故障的诊断分类,能有效消除特征中噪声和野点的影响。将该方法应用于CSTV滤波电路进行仿真实验,结果表明该方法能突出不同故障的特性并正确有效地诊断出多故障类型,综合诊断正确率达到95%,为模拟电路故障诊断提供了新的技术途径。     

混合模型的用户兴趣漂移算法

针对个性化信息服务中的用户兴趣漂移问题,提出了一种新的正态分布密度曲线遗忘函数,该函数符合用户兴趣遗忘的规律.并且将用户模型定义为长期模型和短期模型相结合的混合模型,其中短期模型使用最近最久未使用的滑动窗口算法进行更新,长期模型采用正态渐进遗忘算法进行更新.实验表明,该方法能够较迅速地发现和准确地跟踪用户的兴趣变化,提高了个性化信息服务的效率.