基于AT89C51的高精度超声波测距系统

设计了一种高精度超声测距系统,介绍了系统的组成及功能、电路工作原理、软件设计、试验结果。该系统使用高性价比的AT89C51作为控制器,通过设计测温电路、双比较器的接收电路以及修正系统延迟时间等一些改进措施,克服了当今测距系统低精度的缺点。试验结果表明,该测距系统在0．4m-5m内,测距误差小于1％,能够适用于高精度要求场合。     

采用曲面设计的LED前照灯建模及配光分析

LED作为汽车前照灯的光源在节能和效率上具有优势,本文研究了使用半导体LED光源前照灯的反射镜曲面的设计方法,并进行了配光验证分析。根据前照灯近光配光标准、LED光源特点和反射镜曲面设计,作者建立了新颖的LED前照灯的设计模型,包括LED光源模拟、反射器曲面设计、透镜设计单元和配光分析。作者提出不规则三维曲面作为反射镜的方法,并实现了LED前照灯的照明计算仿真。文章最后分析了实验结果,并指出LED前照灯的前景和未来大功率LED汽车前照灯发展的关键技术。     

WCDMA空中接口的物理层测量

本文对空中接口的技术进行了简单的介绍,着重描述了WCDMA空中接口的结构与功能。并从测量可实现的角度出发,给出了对物理层性能指标和过程进行测量的方案,开发设计了测量分析软件。通过测量的结果,对网络的性能进行了分析。     

A review of smart homes- present state and future challenges

In the era of information technology, the elderly and disabled can be monitored with numerous intelligent devices. Sensors can be implanted into their home for continuous mobility assistance and non-obtrusive disease prevention. Modern sensor-embedded houses, or smart houses, cannot only assist people with reduced physical functions but help resolve the social isolation they face. They are capable of providing assistance without limiting or disturbing the resident's daily routine, giving him or her greater comfort, pleasure, and well-being. This article presents an international selection of leading smart home projects, as well as the associated technologies of wearable/implantable monitoring systems and assistive robotics. The latter are often designed as components of the larger smart home environment. The paper will conclude by discussing future challenges of the domain.     

Lot streaming for product assembly in job shop environment

Assembly job shop scheduling problem (AJSP) is an extension of classical job shop scheduling problem (JSP). AJSP starts with JSP and appends an assembly stage to the completed jobs. Lot streaming (LS) technique is a process of splitting jobs into smaller sub-jobs such that successive operations can be overlapped. This paper combines, for the first time, LS and AJSP, extending LS applicability to both machining and assembly. To solve this complex problem, an efficient algorithm is proposed using genetic algorithms and simple dispatching rules. Experimental results suggest that equal size LS outperforms varied size LS with respect to the objective function.     

Social network,social trust and shared goals in organizational knowledge sharing

The aim of our study was to further develop an understanding of social capital in organizational-knowledge-sharing. We first developed a measurement tool and then a theoretical framework in which three social capital factors (social network, social trust, and shared goals) were combined with the theory of reasoned action; their relationships were then examined using confirmatory factoring analysis. We then surveyed of 190 managers from Hong Kong firms, we confirm that a social network and shared goals significantly contributed to a person's volition to share knowledge, and directly contributed to the perceived social pressure of the organization. The social trust has however showed no direct effect on the attitude and subjective norm of sharing knowledge.     

P2P系统中基于副本链的一致性维护算法

提出一种无结构纯P2P的副本一致性维护算法。利用副本节点发起的第一次更新消息在P2P网络中的广播,由其他收到消息的副本节点给出响应,构建副本链。副本链建立后,更新消息在副本节点间进行传播,不再在网络中洪泛。副本链的维护通过记录首次发起更新的副本节点IP地址完成。仿真试验证明该算法是简单有效的。     

基于概念的形状分类与识别

基于内容的图像检索已经成为图像检索的一个重要研究方向。其中利用形状特征可以实现形状较为明显的各类图像库的检索。该文对图像形状特征的提取和描述方法进行了较深入地研究,选取其中一部分特征值,分别利用BP神经网络和支持向量机进行形状识别,取得令人满意的实验效果。     

浅谈图书馆网络化建设

目前我国各系统、各类型图书馆的自动化建设有了突飞猛进的发展。尤其是随着国际社会信息高速公路计划的实施,因特网技术的普及,我国图书馆界提高了对自动化、网络化建设的认识,逐渐加大了图书馆自动化建设的投资力度。实现图书馆网络化,是今后图书馆得以生存、发展的关键。     

C语言程序设计教学方法探析

语言是一种被广泛应用的计算机语言,它已成为高校计算机教学的重要内容。本文结合教学实践,探讨C语言教学中培养学生编程能力的途径,探索C语言程序设计的教学方法,解决C语言程序设计存在的问题,旨在进一步提高C语言程序设计教学效果。