嵌入式Linux系统在S3C2410开发板上移植的关键环节

本文主要是对基于嵌入式Linux在S3C2410开发板上的移值过程所需要的三个重要文件:BootLoader引导程序uboot、Linux内核的映像文件zImage、根文件系统rootfs的制作过程,以及怎样将这三个文件移植到自己开发板上所涉及到的一些关键环节作了详细的介绍说明。     

EMS型高速磁浮列车自适应导向控制器设计

EMS型高速磁浮列车导向系统的工作条件变化范围大,采用一般方法设计的控制器无法在整个工作范围内保持一致的控制性能。为了解决这个问题,研究了自适应导向控制器的设计方法。首先,建立了导向系统的数学模型,通过设计电流环使模型降阶;并分析了导向系统参数的变化原因及特性,在此基础上采用自校正的自适应控制理论,设计了参数自适应的导向控制器。仿真结果表明,该控制器较好地解决了导向系统在整个工作范围内特性不一致的问题。     

Design of an auditory guidance system for the blind with signal transformation from stereo ultrasonic to binaural audio

We have designed an auditory guidance system for the blind using ultrasonic-to-audio signal transformation. We first investigated the system requirements, and designed a simple but useful portable guidance system for the blind. The system derives visual information using multiple ultrasonic sensors, and transforms it to binaural auditory information using a suitable technique. The user can recognize the position of obstacles and the surrounding environment. The system is composed of two parts. One is a glasses-type system, and the other is a cane-type system with guide wheels. The former functions as an environment sensor, and the latter functions as a clear-path indicator. Wide-beam-angle ultrasonic sensors are used to detect bojects over a broader range. The system is designed as a battery-supplied portable model. Our design is focused on low power consumption, small size, light weight, and easy manipulation.     

GEOMORPHIC RESPONSES TO CHANGES IN INSTREAM FLOWS: THE FLOW‐CHANNEL FITNESS MODEL

The flow‐channel fitness model is a conceptual and practical model for predicting the qualitative response of alluvial channels to modifications of flow regimes. ‘Fitness’ refers to the size of channels compared with the flows they convey, with the terminology derived from traditional geomorphic concepts of overfit and underfit streams. The qualitative predictions refer to whether channels experience aggradation, degradation or relative stability, and whether aggradation or degradation is dominated by width or depth. The model is based on transitions among seven possible fitness states, triggered by key thresholds of sediment supply versus transport capacity and shear stress versus shear strength, and requires that potential changes in sediment supply and water surface or energy‐grade slope also be accounted for. The fitness approach can be used where only relative values and changes are known, as is illustrated in three example applications from Texas. The flow‐channel fitness model synthesizes key elements from several existing approaches to predicting geomorphic responses to changes in flow and is intended to augment rather than replace quantitative approaches, providing a predictive tool where the data requirements and assumptions for quantitative models cannot be fully met. Copyright © 2012 John Wiley & Sons, Ltd.     

三峡库区生态屏障范围界定

为有效保护三峡库区生态环境,应在库区175m淹没线以上建立生态屏障区。本文针对生态屏障的内涵及其具有的功能,提出了具体的生态屏障界定标准并建立了数学模型,提出了生态屏障建设相对适宜度。以忠县洋渡镇作为实例,利用Grid-Xinanjiang产流模型,计算研究区域内各网格单元的产流开始时间;利用网格水滴汇流模型,统计研究区各网格单元到达库区175m淹没线的汇流时间;利用收集到的地形、地貌和土地利用等资料统计研究区各单元的地形起伏、土壤质地、生态屏障投资费用等情况,在此基础上得到了洋渡镇生态屏障建设相对适宜度分布情况。通过计算缓冲区情景与高程情景下不同阈值的生态屏障平均相对适宜度变化曲线,确定了相应情景的生态屏障范围阈值;并通过对比2种阈值的生态屏障范围与适宜度的分布图,认为高程情景优于缓冲区情景。     

Noise analysis compact differential evolution

This article proposes a compact algorithm for optimisation in noisy environments. This algorithm has a compact structure and employs differential evolution search logic. Since it is a compact algorithm, it does not store a population of solutions but a probabilistic representation of the population. This kind of algorithmic structure can be implemented in those real-world problems characterized by memory limitations. The degree of randomization contained in the compact structure allows a robust behaviour in the presence of noise. In addition the proposed algorithm employs the noise analysis survivor selection scheme. This scheme performs an analysis of the noise and automatically performs a re-sampling of the solutions in order to ensure both reliable pairwise comparisons and a minimal cost in terms of fitness evaluations. The noise analysis component can be reliably used in noise environments affected by Gaussian noise which allow an a priori analysis of the noise features. This situation is typical of problems where the fitness is computed by means of measurement devices. An extensive comparative analysis including four different noise levels has been included. Numerical results show that the proposed algorithm displays a very good performance since it regularly succeeds at handling diverse fitness landscapes characterized by diverse noise amplitudes.     

基于人工鱼群的交通诱导系统最优查询研究

与齐齐哈尔市公安交通警察支队交通控制中心合作开发,并以齐齐哈尔市路况为实际进行凋研,将改进的人工鱼群算法应用于交通路径诱导系统数据库优化查淘中,算法提高了最优路径查询的效率。对人工鱼群算法进行了改进,引入贝叶斯变异算子和十字交叉变异算子,避免了算法局部寻优能力差和收敛速度慢等弊端。仿真实验表明算法是正确有效性的。     

商洛市老年人体育健身意识调查研究

通过查阅文献,发放问卷等方法,对商洛市区老年人健身现状进行调查分析商洛市区老年人健身意识,较客观地反映出商洛市区老年人的健身现状,找出存在的主要问题,从而为商洛市社区体育管理提供决策依据,并为老年人科学健身提出相关发展对策.     

Observer-based Guidance Law Accounting for Second-order Dynamics of Missile Autopilots

Accounting for the missile autopilot as second-order dynamics, an observer-based guidance law is designed based on the dynamic surface control method. Some first-order low-pass filters are introduced into the design process to avoid the occurrence of high-order derivatives of the line of sight angle in the expression of guidance law such that it can be implemented in practical applications. The proposed guidance law is effective in compensating the bad influence of the autopilot lag on guidance accuracy. In the simulations of intercepting non maneuvering targets, targets with step acceleration, and targets with sinusoidal acceleration respectively, the guidance law is compared with the adaptive sliding mode guidance law in the presence of missile autopilot lag. The simulation results show that the proposed guidance law is able to guide a missile to accurately intercept a maneuvering target, even if it escapes in a great and fast maneuver and the autopilot has a relatively large lag.     

英语教学中应注意培养学生的自主学习能力

自主学习是大学生学习的主要方式,它是大学生全面发展的一个必要条件,因此学生的学习好坏与本身是否具有一定的自主学习能力有很大关系。而自主学习能力的培养需要在教师的指导下,通过学生的实践,不断总结,才能不断提高。本文根据大学教学实践,就如何培养学生的自主学习能力以及教师的引导作用进行了探讨。