Railroad electrification in the United States

The history of railroad electrification falls into three phases that we might designate the primitive, the pioneer, and the mature. The first was the period of preliminary experiment covering the mid-Nineteenth Century. The second, concentrated in the decade of 1895- 1905, was marked by the first successful installations in Europe and the United States. The third, the age of technological maturity, grew directly out of the previous period.     

Underground transmission in the United States

The means for providing underground transmission of large quantities of electric power at a reduction in present-day cost by at least an order of magnitude ranks among the high imperatives of today's research efforts. Demand for the expansion of ``undergrounding' is soundly based upon such factors as the rapid growth of cities, the doubling of power requirements with every passing decade, and esthetic objections to the appearance of overhead lines. Unfortunately, at the present time, such expansion is possible only at excessive cost. The authors present the problem as it exists within the United States, and offer solutions that are commensurate with the state of the art.     

IN rollout in the United States

Individual perspectives on advanced intelligent network (AIN) implementation are presented from four regional companies in the Unites States: Bell Atlantic, BellSouth, Ameritech, and US WEST. These perspectives range from trial to deployment activities and address a range of capabilities supported by the AIN architecture. AIN participation by all regional companies in the United States is summarized     

打击美国面临的虚假信息(译文)

在过去的几年里,美国联邦政府在解决网上虚假信息问题上取得了长足的进步,但在这一领域取得有效进展的重要结构性障碍依然存在。最主要原因是没有明确指定的机构和相关部门来统筹所有工作,当前没有一个联邦实体拥有监督、权力或资源来承担打击虚假信息的责任。美国网络空间日光浴委员会(CSC)对网络支持的虚假信息进行了深入的研究,提出了美国可以采取的措施,以增强对虚假信息的抵御能力,特别是来自外国行为者的虚假信息。CSC提出了七项建议,以减少信息生态系统中的虚假信息,并增强个人和社会对虚假信息和恶意外国影响的适应能力。     

Digital TV in the United States

With fat prices and lean content, fewer than 20000 digital TV sets have been sold in the four months since the launch of terrestrial digital broadcasting in the USA. However, expectations are high for the greatest broadcast revolution since the introduction of colour TV. The article discusses what's available in digital TV, alternative displays, digital TV for the PC, and the future of digital TV. Insets discuss antennas for digital TV, programs available, data compression and scaling, digital TV and time zones, pioneering digital TV products, digital TV formats, and digital TV abroad     

IPv6在美国

IPv6在美国至今未热 IPv6是用以取代IPv4的下一代互联网协议。它的发源地是在美国,于 1994年由IETF制定。其设计初衷是为了解决互联网上的地址空间问题。目前,IPv6在亚洲和欧洲受到的关注远远超过在美国受到的关注。例如,瑞典的 TeliaSonera、日本的NTT与其它日本公司以及中国的运营商,对网络向IPv6 过渡都已经作出非常明确的承诺,但是北美的运营商却没有作出类似的承诺。 IPv6本身是没有问题的,它是一个非常稳固的协议。IPv6相比IPv4的优点十分明显。它使地址空间增加了数万     

Wireless User Perspectives in the United States

The perspective of typical wireless service users in the United States is examined. Voice, data information, security, and location-based services and their expected evolution over the next few years is discussed. Handset design is considered with emphasis on handset evolution as data and location-based services emerge.     

Educating microwave engineers in the United States

Three knowledge areas in which a microwave engineer needs to be educated are reviewed, and implementation means discussed. It is shown that microwave engineering education in the US occurs primarily after receipt of the first (bachelor's) engineering degree. The inevitability of specialized academic education within the field of microwave engineering is pointed out. Overall results from a broadly based survey of US electrical engineering departments' microwave engineering programs are presented. They include information on master's and doctorate degrees awarded, faculty, and sources and level of research funding. Additional reference sources which contain information on US microwave engineering are identified. Opportunities for making educational improvements on the graduate level of this multifaceted engineering specialization, which is not centrally regulated, are pointed out and illustrated by a specific example     

Fiber-Based Broadband-Access Deployment in the United States

After more than 20 years of research and development, a combination of technological, regulatory, and competitive forces are finally bringing fiber-based broadband access to commercial fruition. The three main approaches-hybrid fiber coax, fiber to the cabinet, and fiber to the home-are each vying for dominance in the industry, and each has significant future potential to grow customers and increase bandwidth and associated-service offerings. Further technical advances and cost reductions will be adopted, eventually bringing performance levels and bandwidth to gigabits-per-second rates when user demand warrants while keeping service costs affordable     

Online distance education in the United States

Distance education is not a new phenomenon. Correspondence courses have been around for many years. Instructional television is a much newer phenomenon, but we nonetheless have decades of experience. However, currently we are experiencing a “virtual land rush” (some would say “gold rush”) in distance education because of the advent of the Internet. This article examines why this is occurring, provide an overview of online distance education activities in the United States, and present a survey of the relevant technologies and their prospects     

美国地面数字广播

数字广播技术，从80年代后期先后在卫星数字电视、地面数字电视和CATV媒体中有了很大的发展。其中卫星数字电视与地面数字电视，不仅在高画质和多频道广播方面具有突出的优异性，而且作为CATV系统的优质节目源也在发挥着巨大的作用。最近，数字广播中双向互动广播的发展，例如地面数字     

The United States in space

The US program is examined in three contexts: its position internationally, its role domestically, and NASA's workings internally. Some of the principal issues explored are: what it means for NASA to be simply a lead agency instead of the sole agency charged with implementing the US space program; whether the types of technical and managerial troubles NASA has recently experienced are different in quality from the troubles it had during the Apollo era; how the various pressures to which it is being subjected are effecting its internal ways of doing business; and whether there are lessons from the experiences of other nations' space programs and their ways of overseeing projects are doing business that could be useful to the US space program, and vice versa     

Evolution of ISDN towards broadband ISDN

Worldwide activities to evolve integrated services digital network (ISDN) into an optical-fiber-based universal broadband network have resulted in the first baseline documents, such as CCITT Recommendation I.121. The asynchronous transfer mode has been established as a key element of broadband ISDN (BISDN). The adoption of the G.707-709 recommendations on the new digital transmission hierarchy will also strongly influence further BISDN development. The author presents the current state of the BISDN discussion, especially within CCITT, briefly addressing broadband services and then concentrating on the user-network interface, as its definition is of utmost importance with respect to the introduction of a worldwide unique BISDN. Network scenarios and evolution and interworking aspects of the arising broadband realizations are also addressed     

Switching in the Broad-Band ISDN

The enhancement of ISDN with broad-band services is investigated from the viewpoint of switching systems. Approaches in system architecture and switching technology are described. The extension of an ISDN switch with broad-band modules is presented as an example.     

关注美国机载激光武器(ABL)计划

机载激光武器（ABL）是拦截处于助推段弹道导弹的激光武器。介绍了ABL汁划的由来并根据其作战任务,分析了其系统组成和各部分担负的任务,系统阐述了其发展计划,并对项目进展进行了预测。     

Foreign R&D in the United States

A new study reveals a marked rise in US activity of R&D by foreign companies. How large is direct foreign investment in R&D in the USA? What exactly do these facilities research and develop? Why have non-US companies set up new operations or expanded existing facilities for R&D in the USA? How do these firms decide where to locate? To address these and related questions, the operations of over 50 European, Japanese, and South Korean R&D facilities were studied. All belong to the the electronics, biotechnology or automotive industries. The results of this study are analysed     

美国的技术性贸易措施(一)

一、美国的技术法规体系和有关联邦政府机构 (一)美国的法律体系 美国是一个联邦制的国家,其法律是一个分散的体系,是由联邦法律和州法律组成的。联邦法律高于州法律,但是联邦法律只能在联邦宪法授权的……     

美国机载激光武器发展-ABL计划

介绍了美国机载激光武器(ABL)计划,分析了ABL武器的组成、工作原理、战技指标和作战运用设计,进而从概念设计、技术验证、分系统集成测试和全系统综合试验四个阶段总结回顾了ABL计划的发展历程,最后从技术制约、作战运用、政策变化、运营管理四个方面探讨了ABL计划失败的原因,并从风险控制、关键技术评估、全寿命需求论证与考核等方面给出了研制发展高新技术武器的启示。