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1.
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  相似文献   

2.
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。  相似文献   

3.
Digital TV in the United States   总被引:2,自引:0,他引:2  
《Spectrum, IEEE》1999,36(3):39-41
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  相似文献   

4.
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.  相似文献   

5.
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.  相似文献   

6.
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  相似文献   

7.
Planning for implementation of ISDN is proceeding at a rapid rate throughout the United States. Planning for nationwide deployment of common-channel signaling to support database access, as well as internode signaling for ISDN is also underway. This paper describes planning for trials and initial applications of ISDN and common-channel signaling for service starting in late 1986 through early 1988, as well as ISDN demonstrations, some already in operation. In addition, this paper discusses the network and regulatory environment for ISDN implementation in the United States, standards for the U.S. environment, and trials of transition services.  相似文献   

8.
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.  相似文献   

9.
Online distance education in the United States   总被引:7,自引:0,他引:7  
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  相似文献   

10.
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  相似文献   

11.
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  相似文献   

12.
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  相似文献   

13.
14.
关注美国机载激光武器(ABL)计划   总被引:6,自引:0,他引:6  
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。  相似文献   

15.
Serapio  M.G.  Jr. Dalton  D.H. 《Spectrum, IEEE》1994,31(11):26-30
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  相似文献   

16.
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……  相似文献   

17.
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。  相似文献   

18.
19.
本文介绍了美国隐蔽字幕电视广播的发展,显示格式,数据码格式及传送格式  相似文献   

20.
二、美国的标准体系 (一)自愿性和分散性的标准体系 美国的标准体系是自愿标准体系,即各有关部和机构自愿编写、自愿采用。在自愿性国家标准体系中美国国家标准学会(ANSI)充当协调者,但ANSI本身并不制定标准,专业和非专业标准制定组织、各行业协会和专业学会在标准化活动……  相似文献   

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