网上考试系统

本论文主要阐述网上考试系统的后台操作过程及考试一些关键技术。该系统包括学生考试子系统和管理员管理子系统两部分。考生进入考生界面后。可以根据事先设置的考题进行随机抽取考题。并开始考试计时,考试时间到,系统强制考生退出并自动交卷。及对客观题的自动评分、存档。管理员进入管理员界面可以对考试科目、题库、试卷等进行设置和管理。因此本文侧重于阐述这两个子系统的设计与实现。     

Key issues in the management of information systems: A Hong Kong perspective

The results of a survey are presented on the perceived importance of 20 IS issues in Hong Kong in 1994 and in the next five years. The survey was based on studies carried out in the USA and Taiwan. The major issues which changed were a decline in the importance of recruiting and maintaining a skilled workforce (IS human resources), accompanied by an increase in the importance of the need for a good communications network (Telecommunications). Comparing the results with those of the USA and Taiwan revealed seven issues common to all the three studies. In particular, the ability to anticipate and adapt to the changing face of IS (IS strategic planning) was a top three issue for the USA, Taiwan and Hong Kong.     

Control strategies for transients of hydrogen production plant in VHTR cogeneration systems

Operability of Very High Temperature Reactor (VHTR) hydrogen cogeneration systems in response to abnormal transients initiated by the hydrogen production plant is one of the important concerns from economical and safety points of views. The abnormal events in the hydrogen production plant could initiate load changes and induce temperature variations in a primary cooling system. Excessive temperature increase in the primary cooling system would cause reactor scrams since the temperature increase in the primary cooling system is restricted in order to prevent undue thermal stresses from reactor structures. Also, temperature decrease has a potential propagation path for reactor scrams by reactivity insertions as a consequence of the reactivity feedbacks. Since suspensions of reactor operation and electricity generation should be avoided even in case of abnormal events in the hydrogen production plant from an economical point of view, an establishment of a control scheme against abnormal transients of hydrogen production plant is required for plant system design.In the present study, basic controls and their integration for the GTHTR300C, a VHTR cogeneration system designed by JAEA with a direct Brayton cycle power conversion unit and thermochemical Iodine-Sulfur process hydrogen production plant (IS hydrogen production plant), against abnormal transients of IS hydrogen production plant are presented. Transient simulations for selected load change events in the IS hydrogen production plants are performed by an original system analysis code which enables to evaluate major phenomena assumed in process heat exchangers of the IS hydrogen production plant.It is shown that abnormal load change events are successfully simulated by the system analysis code developed. The results demonstrated the technical feasibility of proposed controls for continuous operation of the reactor and power conversion unit against load change events in the IS hydrogen production plant.     

Concentration of HIx solution by electro-electrodialysis using Nafion 117 for thermochemical water-splitting IS process

An experimental study of applying electro-electrodialysis (EED) for improved HI concentration in the HIx solution, a mixture of HI–I₂–H₂O of approximately quasi-azeotropic compositions has been carried out in the conditions of around 90 °C and using Nafion 117 and graphite electrodes. A range of 25–80% increase in initial current efficiency of HI molality in catholyte is measured with the use of EED. In general, the efficiency increases with increasing iodine molality and weight ratio of anolyte solution to catholyte solution. The EED performance degrades in time. In some cases, the HI concentration limits are observed. Electric conductivity of the HIx solution, overvoltage of electrode reaction, and the membrane voltage drop is measured in a temperature range of 20–120 °C. It is found that the EED cell voltage, which is an important cell performance parameter, is governed by the membrane voltage drop.     

An overview of instrumentation and control systems of a Korea standard nuclear power plant: A signal interface standpoint

This paper presents an overview of instrumentation and control (I&C) systems of a pressurized water reactor (PWR) type nuclear power plant (NPP) in Korea. Yonggwang unit 3, which was constructed as a basis model for a Korea standard nuclear power plant (KSNP), is selected as an example for the presentation. This overview is derived from analyzing the I&C systems based on a top-down approach. The I&C systems consist of 30 systems. The 183 I&C cabinets are also analyzed and mapped to the systems. The overview is focused on an interface between the systems and the cabinets. This information will be used to understand the implementation of the I&C systems and to group the systems for an upgrade.     

论我国企业信息化成功之路

本文通过对西方企业信息化历程与经验的总结 ,对比我现阶段信息化特征 ,提出我国企业信息化应重点关注的方面和方案选择原则。     

一种重要抽样仿真方法的研究及应用

介绍了蒙特-卡洛仿真原理,分析了改进型的蒙特-卡洛仿真即重要抽样(IS)的原理及其在通信中的应用,特别是在高速光纤通信的偏振模色散(PMD)仿真中的应用价值.实验证明,采用重要抽样的仿真方法可以得到大差分群时延(DGD)值的小概率事件,并且系统配置比用蒙特-卡洛的仿真方法简单得多.     

基于WWW的敏捷制造信息系统

信息系统作为信息时代企业赖以生存的基石,在当今日益激烈的国际竞争中发挥着不可替代和独具特色的作用。本文基于敏捷制造对企业信息环境提出的要求,对敏捷制造信息系统提出了构建方案,包括系统的结构模型与技术基础,以及一些有待解决的问题。该系统借助于软件智能体作为软件构件,利用数据可视化技术设计企业运作的规划与管理辅助工具,而信息交换接口则用面向对象方式来实现。所采用的关键技术使企业的信息支撑体系具备对国际大环境变化的快速响应,更加有利于发挥资源的总体效益,增强企业的敏捷性,这也正是企业信息系统的最终目标。     

Board IT Governance in Context: Considering Governance Style and Environmental Dynamism Contingencies

ABSTRACT

We theorize that IT governance (ITG) by the board of directors is most effective when there is a fit between the dynamics of the business environment and the governance style through which board ITG is delivered. Survey findings from 110 board members largely supported these assertions. Findings show that authoritative governance style and environmental dynamism represent important boundary conditions for the efficacy of board ITG to achieve performance gains. Research and practical implications are discussed.