突发信道下无线ATM的前向差错控制方案

在无线ATM网络中，无线信道的高误码率和突发特性要求对无线ATM信元进行较强的误码保护。本文提出了一种有效的前向差错控制（FEC）方案，对信元头采用较强的FEC，对信息域采用较弱的FEC，并针对信道特性和采用的前向差错控制编码的特点进行元头信元内交织，文中对无线ATM信元在突发信道下的信元丢失率和信元信息错误率进行了分析，仿真结果表明该方案在降低信元信息错误率的同时有效地降低了信元丢失率。     

基于无线PKI的移动支付认证鉴权服务平台研究

移动电子商务已经成为市场发展的趋势,但移动支付的安全问题也日益突显。为了保证移动支付的安全,在分析了无线PKI系统的结构和实现流程的基础上,设计了基于无线PKI的移动支付认证鉴权服务平台的框架和体系结构,进而设计了了移动支付认证鉴权服务平台的构建过程,用以指导移动支付认证鉴权服务平台的开发和实现。     

Reexamining the effect of packet pricing in the wireless internet

In this paper, we compare the market performances of circuit pricing whereby users are charged based on their length of usage time with packet pricing whereby users are charged based on the amount of information received. We show that, if packet pricing is introduced, the market price rises contrary to a widely held belief, but that the overall social welfare is unambiguously increased. Also, we show that a move to packet pricing lowers the price of multimedia transmission which requires a much higher speed, thereby increasing the usage of multimedia data in the absence of congestion, although this may not be the case in the presence of congestion.     

通信领域中的MEMS器件及发展动态

微电子机械系统(MEMS)技术在通信领域中有着广泛的应用前景，本文介绍了在无线通信和光通信中的MEMS器件如MEMS电感、电容、开关、滤波器、光检测器等MEMS器件的原理、结构和发展概况，指出了MEMS器件发展所面临的问题和方向。     

考虑伪码跟踪误差影响的码片内多径分离研究

<正> 刘光溪同志是我国第一位国际贸易专业WTO研究方面的博士并作为中国代表团主要成员参与了13年中国复关/入世的实质性谈判工作,写过多本有关世贸组织和区域经济合作方面的专著,《碰撞、融合、发展——亲历13年复关/入世谈判的思索》是他在这方面的一本新著。已由上海人民出版社于2002年2月正式出版发行。     

Informational mobility and productivity: Finnish evidence

The labor productivity effects of portability and connectivity of information and communication technology (ICT) are studied with Finnish firm-level data. It is found that a computer with only processing and storage capabilities boosts labor productivity by 9% (corresponding to 5% output elasticity), portability by 32%, wireline connectivity by 14%, and wireless connectivity by 6%. The findings are in line with previous literature and comparisons to ICT costs suggest that firms equate marginal costs and returns. Although increasing ICT penetration can no longer be a major source of productivity growth in developed economies, the relatively new characteristics studied can.     

Disconnecting: Understanding decline in universal service

At a time when choices for voice service and funding for universal service were growing, the United States experienced an unprecedented drop in household telephone penetration. Universal service in voice telephony is generally taken for granted in the United States. However, recent data from the FCC shows a significant decline in the number of U.S. households that have a telephone of any kind (including mobile), from a peak in telephone penetration of 95.5% in March 2003 down to 92.9% in November 2005. This decline is both statistically significant and meaningful, as approximately 2.6% of U.S. households could not easily reach 911 for emergencies. This study uses regression analysis of state-level data to determine what drove this decline in universal service. The results demonstrate that the recent decline in universal service in the U.S. is driven by an increase in black population, inadequate consumer protection laws, and increases in wireless telephones per capita. Lifeline effectiveness does not appear to mitigate the decline in penetration, while Link-Up effectiveness may have a limited effect.     

超宽带无线通信及其关键技术

本文从落实科学发展观、充分利用国内外两个市场、两种资源、拓展发展空间以及更好地处理内需与外需、利用外资与利用内资关系等角度论述统筹国内发展和对外开放的蕴涵,并从发展国民经济全局和实现现代化战略目标出发提出统筹国内发展和对外开放应采取"4个相结合"的对策措施。     

基于JUMMSE准则的前向分数间隔判决反馈均衡器

研究了前向分数间隔判决反馈均衡器的原理与结构，并推导了基于联合无偏差MMSE(JUMMSE)准则设计的最优解。文中讨论了均衡器长度对误符号率(SER)性能的影响。仿真结果表明，在较高的信噪比、选择恰当的均衡器长度时，这种均衡器对于高频信道的均衡效果是显著的。     

Scientific eventuality or science fiction: The future of people with different abilities

Consider this, we are living in a future [in-part] imagined over 30 years ago- in science fiction film and books. We may envision that 30 years from now we could live in a future with technology developed from the concepts we see in science fiction today. In this paper, the concepts of disability are challenged in the future based on the technologies imagined in the science fiction genre of the present and past. Focused on the sub-genre, Cyberpunk, current mainstream, as well as new emerging technologies inspired by science fiction are reviewed. Future disability is reimagined dependent on continued support and acceptance of the emerging technology. If our past is any indication, our future may lie in the conceptual and slightly implausible figments of our science fiction-based imaginations. However, the cultural shift will significantly impact our laws, regulations, and policies, as well as introduce new societal concerns.