S波段DDS/PLL频率合成技术研究

DDS是一种数字波形合成技术，具有频率转换速度快、频率分辨率高、相位噪声低等优良性能，因此利用DDS作为可变参考源是比较理想的。本文采用DDS作为参考源驱动PLL频率合成器，实现了一个用于S波段遥测接收机的DDS/PLL频率合成器，同时对DDS/PLL频率合成器的输出特性进行了理论分析，并给出了实验结果。     

利用CDMA机制实现小卫星星座控制与通信

本文介绍了小卫星及星座的一些基本情况，分析了CDMA技术的优势，初步探讨了CDMA技术在小卫星测控方面的应用。     

Language and tourism

The sociolinguistic study of verbal encounters in touristic situations provides an opportunity to exanine communication between different linguistic groups under unusual circumstances: the high temporariness of the foreigners and the high degree of linguistic accommodation of the locals to them. This state of affairs stands in marked contrast to the tendency of guestworkers and immigrants who are less temporary and usually of lower status, to accommodate linguistically to the locals. While accommodation by locals is common to virtually all touristic situations, the degree of proficiency of locals in the tourists' language varies considerably and hence also the extent to which tourists are forced to accommodate linguistically. In an effort to organize the linguistic variation in tourism, a typology of tourist roles is used as the principal framework. The notion of “language brokerage” is introduced. The integration of sociological and sociolinguistic analyses is illustrated by incidental data from the literature on tourism and from fieldwork in Thailand.     

欧盟与亚太主要国家(地区)经济指标

本文以Z85C30芯片的应用为人,着重于HDLC通信的介绍，同时指出了Z85C30芯片在软硬件设计中应注意的问题。     

认知无线电在未来多媒体移动通信中的应用

本文分析企业在引进中高级人才工作中遇到的风险,分析了产生这些风险的原因,风险给社会与企业带来的后果。并在此基础上,结合实践工作中的经验,提出了在中高级人才引进过程中防范风险的应对措施。     

基于主从多机通信的暖房自动温控系统的设计与实现

基于单片机的主从式多机通信原理，设计了一个控制系统。该系统可用于控制暖房的温度和湿度。同时给出了通信接口和软件的设计。     

Computer-supported cooperative negotiations

This article describes an environment for interactive negotiations based on current and emerging information technology. Over the past few years a suite of methods, tools, and techniques have emerged which promise to revolutionize the negotiations planning and decision-making processes. Some of these technologies include collaborative computing, electronic publishing, intelligent systems, and networked communications—all supported by a network of processors, applications, and data bases. This article explores these opportunities by examining how the methods, tools, and techniques might all combine to facilitate “computer-supported cooperative negotiations.”     

网络控制系统的分析与应用

网络控制系统(NCS)是一个全新的研究领域,文章通过对网络控制系统的分析,指出了网络控制系统的特征及存在的技术问题,从控制性能和服务质量2个方面进行讨论,指出了网络控制系统的发展方向。     

The emergence of technology systems: knowledge production and distribution in the case of the Emilian plastics district

The emergence of technology systems is the result of interdependentdynamics of the generation and diffusion of complementary bitsof localised technological knowledge. Technological communicationis the crucial element assessing the collective conditions underwhich technological knowledge is accumulated and diffused. Thecase study of the emerging Emilian technological system in theplastics sector shows that the synchronic and diachronic localisedinteractions among industrial dynamics, institutional R&Defforts and technological interrelatedness are the determinantsof the systematic production, accumulation and distributionof localised technological knowledge, in turn explaining theorigin and development of the technology system itself.     

浅谈对“教育是一种服务”观念的认识

把教育对象变为服务对象是教育观念一个根本性的转变.尤其是加入WTO后,教育成为一种服务已是时代的迫切呼唤,一个社会化的、开放的、参与国际竞争的中国教育新格局已经到来,只有具有一流服务的学校和教师,才能成为教育竞争的赢家.