Intranets: technologies, services and management

An intranet is a network which facilitates seamless computing and communications-using mostly Internet software and hardware technologies-within a corporation. The key issues, challenges, technological and policy enablers, and driving expectations of customers and/or applications of corporate networks are reviewed. Management of service and information transport are then examined. Various phases in the life cycle of enterprise networks (ENs) are then presented. Finally, one possible path for the evolution of existing ENs to intranets or next-generation ENs is discussed     

Measuring information society: Dynamics of European data on usage of information and communication technologies in Europe since 1995

This paper discusses the alternative definitions of the so-called “information society” (IS) concept provided by the scientific community and argues for the need to multiply quantitative measurements of the penetration of information and communication technology (ICTs) within the various layers of society as a way to solve major theoretical and political issues. The central part of the paper consists of an in-depth analysis of survey data collected between 1995 and 1999 by the European Commission through its “Measuring IS” pan-European surveys. Contrasts among nations and demographic groups are highlighted and interpreted. By constructing an aggregated variable called the information and communication technology adoption scale (ICTAS), the paper looks at information technology in various groups are identified as spectacularly less inclined to use technologies, while trends indicate that further positive evolutions can be expected particularly for Southern countries of Europe if an appropriate policy mix is implemented in the framework of a re-launch of the “IS policy”.     

综合业务卫星通信网的设计

目前的卫星通信系统主要有FDMA／MCPC、FDMA／SCPC、MF-TDMA等技术体制,其中MF-TOMA存在明显优势,分析了帧中继接入及MF-TDMA卫星通信体制的优点。根据用户需求及网络规模,对卫星通信体制进行了选择,设计了一个支持综合业务传输的帧中继MF-TDMA卫星通信系统。对业务量计算、载波数量选择、载波速率选择等系统设计关键问题进行了重点设计。     

Future information and communication technologies

In past issues of this column there have been articles about European public co-funded research programs, funded by the European Commission (EC) and/or national governments [1-3]. Of all these programs, the one with the most relevance and impact, and the largest budget is EC Framework Programme 7 - Information and Communication Technologies (FP7-ICT). In this article we provide an overview of the main research trends in this program for the coming years.     

Standardization of network technologies and services

The relationships between standards organizations is expected to change as service boundaries rapidly become vague and media become unified. The collaboration between these organizations and the generation of common texts on recommendations/standards has already begun. This report surveys several standardization activities that have been focusing on new trends in telecommunication technologies and services brought about by remarkable technical advances. It describes what is happening in the areas of network technologies and new services, what standards have been established, and what is expected in the near future     

Standardization of network technologies and services

Asatani (1994) reported on a variety of topics, including broadband aspects of ISDN (B-ISDN), intelligent network (IN), future public land mobile telecommunication systems (FPLMTS), and audiovisual multimedia services (AVMMS). With the exception of IN, the present report covers progress in those same areas, with a status report on telecommunication management network (TMN) and universal personal telecommunications (UPT). Fora and consortia which may influence standardizations on these topics and standardization activities related to information infrastructure (II) are also reported     

Ethernet-based public communication services: challenge and opportunity

Enterprises and residential customers increasingly take advantage of more sophisticated applications and evolve their business models. At the same time service providers face declining revenues from existing connectivity services. SPs respond to these trends and start to offer highly customized, high-bandwidth network services that complement and interwork with their existing leased line, ATM, or frame relay offerings. Ethernet is quickly becoming the customer UNI of choice. Ethernet, being a packet-based technology, complements IP-based services such as content, voice, data, video, and additional value-added services over a high-speed access connection. Ethernet also provides a flexible high-speed connection to the SP network and eliminates access bottlenecks. Using Ethernet as the common access interface, providers can employ flexible transport services that enable additional value-added services at layer 3 and above. At the same time the rollout of Ethernet services also challenges the installed base, given that bandwidth per customer is usually much higher and additional attributes for tight SLAs apply. This calls for an updated approach to network deployment and rollout: networks need to be planned and built in a service-centric fashion. Starting with a brief look at the driving forces for Ethernet-based public communication services, this article identifies five generic services for Ethernet MANs/WANs and discusses related deployment issues of the different service options, such as the degree of customization, geographic reach and bandwidth profile of the service, as well as evolution aspects of the installed base.     

Telematic services via satellite in Europe

The word ‘telematics’ was used for the first time in France in 1978 by Simon Nora and Alain Minc; it is a contraction of the French words ‘tétécommunications’ and ‘informatique’, and defines a marriage between computers and data transmission networks. This paper describes the five systems which will be implemented to provide telematic services via satellite in Europe during the next few years: EUTELSAT, TELECOM 1, UNISAT, DFS and ITALSAT. The main characteristics of the ‘special service’ transponders are presented, showing that, in Europe, (a) 2 to 5 transponders per satellite will be devoted to the special (telematic) services; (b) 4 satellites out of the 5 use the 12.5–12.75 GHz down-link band for this purpose (only ITALSAT uses the 20 GHz down-link for the same purpose), and (c) e.i.r.p.s at 12 GHz are in the range 40–49 dBW. The ground and space segments corresponding to this new service are presented. The main peculiarity of the ground segment is the exclusive use of ‘small’ earth-stations equipped with fixed antennas and SCPC or 25–60 Mb/s TDMA multiple access equipment. Telematic services include videoconference at 2048 kb/s, voice services, computer-to-computer transfer of data, data distribution, remote printing, electronic mail, high-speed facsimile, offshore voice and data services, digital network overflow, transatlantic digital business etc… Customer bit rates start from 2.4, 4.8, 9.6 and 32 kb/s (for TELECOM 1) up to 2048 kb/s by 64 kb/s steps. Bit error rates are maintained below 10^?6 (standard) or 10^?10 (higher grade) during 99 per cent of the year using FEC. The five networks for telematics via satellite in Europe are independent. A large efficiency improvement of the different services should be obtained through a future interconnection of the various networks via intersatellite links.     

软件通信结构的目标及其构成

近三年来,个人移动通信技术发展异常迅猛。在基础设施方面,第三代宽带CDMA通信系统更是各个厂家必争之地。新技术的不断出现和新的要求的提出使得通信系统更新换代越来越快。如果不能使新旧系统之间具有很好的连续性和继承性,对运营商和用户都是很大的损失和浪费。为了解决这一问题,软件通信结构（SCA）应运而生。SCA建立了独立于设备的结构框架,其目标是确保软件和硬件的可移植性和可配置性,并确保根据SCA开发的产品之间的互通。首先提出SCA的是联合战术无线电系统（JTRS）。之后,软件定义无线电（SDR）论坛也接受SCA规…     

Advanced generating technologies: motivation and selection processin electric utilities

The constant search by electric utilities for advanced methods for generating electricity to meet future demand is discussed. The primary goal is to generate electricity with minimum damage to the environment and to use resources that are abundant. The evaluation of the role of these technologies in the future utility system, considering both quantifiable and nonquantifiable benefits and risks, is discussed from the perspective of the utility planning process     

在应用中不断发展的光纤通信技术

受到世界经济低迷的影响,通信业也经历了极为严重的挫折.作为通信网最基本、也是最主要传输手段的光纤通信也难逃厄运,似乎光通信再也没有了发展前景.事实上,光纤通信技术已经在市场经济的潮流中接受了洗礼,在应用中得到不断的发展.本文试图从几个不同的侧面,介绍光纤通信技术如何适应市场需求而不断发展的情况.     

基于对等网络的医学影像服务系统通讯平台设计与应用

通过建立医学影像对等网络通讯平台,以便于研究对等网络在各医学影像服务中的应用,描述了其组织结构设计与节点管理,阐述了对等节点间在不同区域建立通讯连接的方法,通过远程在线会诊为实例,把医学影像对等网络通讯平台的使用方法进行了详细的介绍。     

Personal communication services: expanding the freedom tocommunicate

Discusses the potential of personal communication services, which allows communication from person to person, regardless of physical location, to change the way people live and work. The problem of spectrum scarcity is examined, and some proposals for increasing the efficiency of spectrum use are presented     

Frequency planning for broadcast services in Europe

The regular lattice theory is a powerful tool to achieve an efficient use of the frequency spectrum when assigning frequencies or channels to broadcast transmitters. In this paper the basis of the theory is explained, and it is shown how it can be implemented in planning broadcasting transmitter networks for AM or FM sound and television. Physical laws and local considerations will, of course, influence the design of networks and some practical examples are given to make clear how they have been taken into account. The theory will be useful not only in building or remodeling actual transmitter networks, but also with the aim of optimizing technical parameters such as channel spacing, transmitter characteristics, etc. In this later case computerized method will be efficient. Regular lattices have been of some help in former ITU planning conferences, and will certainly be of assistance to experts in charge of achieving good plans in the future conferences of the years to come.