高校图书馆资产管理略论

本文结合高校图书馆资产管理现状,分析资产管理工作中存在的问题,并提出有效的管理措施,为建立、健全高校图书馆资产管理制度提出合理化建议。     

基于欧氏空间相似度的云模型协同过滤算法

传统的基于余弦相似度度量的云模型协同过滤推荐算法未考虑特征向量的长度和维度,忽略了三个重要数字特征云期望、熵和超熵的关系,如各数字特征具有不同的性质和权重,导致特征丢失、区分度过小的问题。针对这些问题,提出了一种采用标准化的多维欧几里德相似度计算方法,通过将三个数字特征映射为三维空间的点,计算经指数函数标准化的欧几里德相似度,生成更合理的用户k近邻集,最终产生推荐。实验结果表明,该相似度计算方法能够为云特征向量提供更显著的区分度,并在一定程度上提高了推荐质量。     

关于110 kV线路重合闸的探讨

重合闸在110 kV线路供电过程中起到了非常重要的作用,它关系着电力系统运行的安全性和可靠性。在重合闸投运前,需要模拟系统的运行情况,事前试验可能存在的重合闸形式,及时发现、排除其中存在的问题,确保重合闸能够正确动作。分析了110 kV线路重合闸的原理、功能,并以某案例分析为基础,简要探讨了对110 kV线路重合闸控制的相关认识。     

电感传感器金属探测定位系统设计

本文以 LDC1000电感传感器以及飞思卡尔 Kinetis 系列微控制器 K60为核心,组成具有定位功能的金属探测系统。通过金属的涡流效应,对金属物体进行检测,能够在一定范围内迅速定位出金属物体的精确位置。经实验表明,距离物体中心定位误差不超过4 mm,最小可以检测出2 cm2大小的金属物体。测量数据在单片机中进行处理,软件上采用了数字滤波,进一步减少了误差干扰信号,提高了系统的稳定性与精确性。该系统可通过 LCD 液晶显示屏显示当前金属物体所在具体位置,并利用按键实现人机交互。     

基于双层安全体系的移动办公应用平台设计与实现

针对移动办公应用的需求,采用HTML5技术和Android系统进行开发,本文提出一种基于双层安全体系的移动办公应用平台。系统通过移动中间件实现了多类型移动设备的统一接入,对企业OA、报账系统、公文处理进行了接口设计,无缝接入企业原有系统的数据和报表,并提供了链路安全和应用安全双层安全体系的保障,为企业人员实时、有效地获取相关工作信息提供了便利。     

应用型本科院校“数据结构”课程教学探讨

针对应用型本科院校对学生动手能力要求高,但学生学习"数据结构"课程觉得枯燥无味、难以理解的情况,对课堂教学和课后实训两方面改革进行了探讨。     

Android系统的蓝牙远程控制研究

Android操作系统以开源、界面友好等特点在智能手机、智能手表等可穿戴设备中广泛应用.设备之间通过蓝牙通信进行信息的交互,为了实现远程控制功能,需自定义蓝牙数据结构,实现对普通数据信息和控制信息的区分.在实例中实现了Android手机之间远程控制拍摄照片以及实时预览图像的功能.采用RC4和RSA混合加密方式对蓝牙发送的数据进行加密,来保证发送数据的安全性.     

A modified dynamic surface approach for control of nonlinear systems with unknown input dead zone

This paper focuses on the robust output precise tracking control problem of uncertain nonlinear systems in pure‐feedback form with unknown input dead zone. By designing an extended state observer, the states unmeasurable problem in traditional feedback control is solved, and the lumped uncertainty, which is caused by system unknown functions and input dead zone, is estimated. In order to apply separation principle, finite‐time extended state observer is designed to obtain system states and estimate the lumped uncertainty. Then, by introducing tracking differentiator, a modified dynamic surface control approach is developed to eliminate the ‘explosion of complexity’ problem and guarantee the tracking performance of system output. Because tracking differentiator is a fast precise signal filter, the closed‐loop control performance is significantly improved when it is used in dynamic surface control instead of first‐order filters. The L _∞ stability of the whole closed‐loop system, which guarantees both the transient and steady‐state performance, is shown by the Lyapunov method and initialization technique. Numerical and experiment examples are performed to illustrate our proposed control scheme with satisfactory results. Copyright © 2013 John Wiley & Sons, Ltd.     

Less conservative stability criteria for linear systems with interval time‐varying delays

The problem of the stability of a linear system with an interval time‐varying delay is investigated. A new Lyapunov–Krasovskii functional that fully uses information about the lower bound of the time‐varying delay is constructed to derive new stability criteria. It is proved that the proposed Lyapunov–Krasovskii functional can lead to less conservative results than some existing ones. Based on the proposed Lyapunov–Krasovskii functional, two stability conditions are developed using two different methods to estimate Lyapunov–Krasovskii functional's derivative. Two numerical examples are given to illustrate that the two stability conditions are complementary and yield a larger maximum upper bound of the time‐varying delay than some existing results. Copyright © 2013 John Wiley & Sons, Ltd.