单片机控制泄漏电流测试仪

以8031单片机为核心的泄漏电流测试仪的硬件结构和软件设计。     

电动自行车充电器自动检测系统设计

介绍了基于PC虚拟仪器和VB环境的电动自行车充电器自动检测系统，阐述了系统检测原理，硬件结构设计及应用软件的编制方法，文中还给出了一个实用的恒流放电电子负载电路。     

虚拟专用网的体系结构及实现

提出VPN接入设备的体系结构 ,包括系统的应用模型、层次划分和内部详细结构 ,阐述实现VPN的关键技术。     

Virtual teamwork in very large undergraduate classes

Collaborative work is an important part of tertiary education but it is very difficult to arrange and supervise for extremely large classes of students in their first year. The possibility that computer-mediated communication can be used to facilitate this type of learning is appealing from a pragmatic organisational point of view. This paper explains in detail what a ‘virtual team’ is in the educational context. It reports on an interpretive field study where students taking an introductory course were allowed to choose where and when they did the required collaborative work. The paper discusses the factors that should be taken into account when offering students the option of working as a virtual team. These include factors that influence the students’ choice. The project cannot be considered to have been successful but indicates reasons for the lack of success and suggests contexts in which it would be valuable to repeat the project. The importance of extensive preparation in terms of teaching the students necessary social and technological skills cannot be over emphasised.     

Process and technology challenges in swift-starting virtual teams

Virtual teams often face tight schedules and a need to start quickly and perform instantly. The goal of our study was to enhance understanding of the challenges faced by such teams. We used time–interaction–performance theory as the framework for following the processes and functions within virtual teams working on a systems development task. Our study provided a detailed examination of the group process, applied to virtual teams working under time pressure. The challenges faced by virtual teams in such settings showed that teams must work to enhance their effectiveness in multiple dimensions.     

实用运算放大器网络中的虚地性质

本文提出用一个理想电压控制电流源(VCCS)并接于嵌在一个倒相放大器电路中的实际运算放大器(OP.amp)输入端,虚地性质(VGP)可以扩展到使用的运算放大器单位增益带宽那样高的频率.文中给出用真正运算放大器的VCCS的实用电路.用互补变换法可得出非倒相放大电路图.     

An accurate and practical buffer allocation model for the buffer cache based on marginal gains

A new dynamic buffer allocation strategy based on the notion of marginal gains is presented for the buffer cache that is used by the operating system to store frequently accessed disk blocks in main memory, and the performance of the proposed strategy is compared with those of previous allocation strategies. In the proposed strategy, marginal gain values are predicted by exploiting functions that approximate the expected number of buffer hits per unit time. Experimental results from both trace-driven simulation and an actual implementation in the FreeBSD operating system show that the proposed strategy accurately predicts the marginal gain values for various workloads resulting in significantly improved buffer hit ratios.     

"一步建站"Web管理系统的探讨和实现

“一步建站”Web管理系统是指通过Web界面一次性提交用户资料，系统自动完成为上网建站用户开通虚拟服务器、进行域名解析、创建FTP维护账号及指定租用硬盘空间大小等一系列操作。同时，该系统还可对已开通的用户站点进行管理。     

HVS：一个半现实全景图时空模型

利用实景图象组成具有空间感和时间感的虚拟空间，我们称之为半现实。这种具有空间“上下文”和时间“上下文”能力的半现实全景图可以应用于许多方面。文中描述了这种半现实ＨＶＳ的建模思想，给出了组成时空座标系的方法，并且讨论了实现中的若干问题。     

面向大规模定制的虚拟设计研究

综述了大规模定制的范围经济性和面向大规模定制的基本设计方法，并提出了一个虚拟设计框架，该框架改变了传统的设计模式，利用先进的设计方法学和仿真支撑技术为产品开发提供了最大柔性和敏捷性。同时，它提供了一个多学科合作的设计环境，用户直接参与进设计循环中。最后，结合新型剑杆织机的开发，展示了一个能够支持新产品快速成功开发的虚拟设计环境。