Strategic appraisal of energy models for Mozambique

The needs that an energy supply system must meet are constantly changing, due to technological, social and political reasons. Effective energy planning is a dynamic process that is repeated periodically and adjusts to changing conditions. Energy decision makers and planners are no longer able to rely on inductive decision making since they have to investigate the effect of various decision parameters and possible future changes. To help in this process, models have been developed where estimates of future load growth, candidate power plants, fuels and other key factors can be introduced, from which the planners can evaluate decision parameters and the available alternatives. The paper presents the different methodologies and practices that are used by 11 energy models for energy demand forecasting, supply side management and generation expansion planning, demand side management and integrated resource planning. The paper concludes to the presentation of a strategic appraisal of the examined energy models appropriate for energy planning in Mozambique. Three models are proposed for conducting demand forecasting, generation expansion planning and demand side management. Copyright © 2002 John Wiley & Sons, Ltd.     

Proactive resource allocation for asynchronous real-time distributed systems in the presence of processor failures

We present two proactive resource allocation algorithms, RBA^*-FT and OBA-FT, for fault-tolerant asynchronous real-time distributed systems. The algorithms consider an application model where task timeliness is specified by Jensen's benefit functions and the anticipated application workload during future time intervals is described by adaptation functions. In addition, we assume that reliability functions of processors are available a priori. Given these models, our objective is to maximize aggregate task benefit and minimize aggregate missed deadline ratio in the presence of processor failures. Since determining the optimal solution is computationally intractable, the algorithms heuristically compute sub-optimal resource allocations, but in polynomial time. Experimental results reveal that RBA^*-FT and OBA-FT outperform their non-fault-tolerant counterparts in the presence of processor failures. Furthermore, RBA^*-FT performs better than OBA-FT, although OBA-FT incurs better worst-case and amortized computational costs. Finally, we observe that both algorithms robustly withstand errors in the estimation of anticipated failures.     

本地缓存和代理服务器环境下的网络日志挖掘

介绍了网络日志挖掘的基本概念，提出了一个网络日志挖掘通用系统的结构，分析了本地缓存和代理服务器对日志挖掘的影响，并给出了一种近似解决方案。这种方案通过网络拓扑结构和日志文件记录的结合，将杂乱无章的日志记录组合成具有语义信息的事务记录，从而使挖掘结果更有意义。     

铁通资源管理系统的设计和实现

在分析铁路通信资源结构的基础上,利用地理信息系统技术、数据库技术和客户/服务器(C/S)模式,为铁通(ChinaTietong)各级分公司和运营部门提供一套较为完善的资源管理信息系统。文中分析了铁通资源的结构与资源之间的关联,介绍了系统功能、物理结构及体系结构,详细分析了数据库设计、地理信息系统和系统安全性所采用的关键技术。这套系统的应用对铁通网络管理的现代化将起到重要的推动作用。     

对电视安全播出的几点思考

从电视节目安全播出的角度出发，探讨如何采取切实有效的措施，确保电视节目的安全优质播出，力争使电视台的安全播出上一个新台阶，主要从播控系统的安全可靠性以及管理措施等方面进行阐述。     

"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。     

关于我国资源保障能力的若干思考

资源保障能力是一国综合国力判断的重要指标之一。本文首先界定了资源保障能力的涵义，然后分析了五个对资源保障能力比较重要的影响因素，即资源禀赋、经济发展水平、科学技术因素、政治因素和人们的资源观，最后得出几点我国提高资源保障能力的建议以供参考。     

基于多智能体的数控机床资源共享技术研究

以数控铣床为对象，应用多智能体技术，以解决传统的资源共享所面lI缶的透明度低和效率低下的问题。首先，在分析功能模型的基础上，提出并实现了资源共享的四层网络拓扑结构；其次，构造了面向设备资源共享功能的智能体信息流模型，以实现四层结构之间的交互；其三，定义了智能体状态函数，并以此为依据，建立了智能体协商机制。所开发的原型系统表明，以上成果有效地提高了数控机床资源共享的透明度和效率。     

Mach网络服务器的设计

Ｍａｃｈ网络服务器把本地ＩＰＣ机制透明地扩充到网络环境，为分布式应用提供支持。本文介绍了Ｍａｃｈ网络服务器的功能，内部组织结构及网络通讯的基本过程。     

客户机／服务器计算环境

本文介绍了客户机／服务器计算环境的基本概念和产生背景，阐述了客户机／服务器计算中操作系统的选择原则及企业级客户机／服务器计算环境的特点。