浅析宽带接入网技术及发展趋势

随看网络技术的不断发展,使得用户的宽带接入方式变得更加多样性.本文对现有的宽带接入技术应用情况进行分析,并对当前接入网的发展策略进行一定的探讨.     

应用PPPoE的宽带接入方式研究及接入网设计

根据工作实践分析了宽带以太网用户接入的几种方式，详细介绍了PPPoE的帧格式和工作过程，给出了用户安全性设计和城域接入网设计实例。     

光纤接入网在农村的应用

我国是一个发展中国家,电信产品消费水平普遍较低,目前商业农村光接入网用户还非常少,农村光接入网推广尚处于起步阶段,为此,选择适合我国国情的农村光接入技术,以发展的眼光分析农村光接入网投资效益,对推动我国农村光接入网的普及至关重要.     

浅谈城市光纤接入网的规划设计

根据城市接入网的现状及近期用户需求,提出城市光纤接入网勘察的主要内容。结合光纤接入网分层规划模型,对城市光纤接入网的主干层、分配层和引人层的规划设计进行了探讨。     

更快捷的ADSL上网技术

随着Internet的爆炸式发展,在Internet上的商业应用和多媒体等服务也得以迅猛推广。要享受Internet上的各种服务,用户必须以某种方式接入网络。为了实现用户接入网的数字化、宽带化,提高用户上网速度,光纤到户(FTTH)是用户网今后发展的必然方向,但由于光纤用户网的成本过高,在今后的十几年甚至几十年内大多数用户网仍将继续使用现有的铜线环路,于是近年来人们提出了多项过渡性的宽带接入网技术,包括N-ISDN、Cable Modem、     

关于通信客户接入工程的前评估研究

用户接入网是将用户接入通信线路的网络。随着通信技术的飞速发展,无论从用户接入部分在网络中的重要作用或从技术复杂程度方面看都促使其受到充分重视,使得其规模和采用的网络传输系统技术、接入方式、传输介质和传输信息的种类及需要占用的带宽等都刁;便做统一的规范,并难于统一管理和维护。应特别注意的是用户接入网作为末端用户和公用网之间的链路是为居民和商业用户提供充分带宽应用的关键,直到现在为止,仍然是整个通信网络的带宽瓶颈。     

宽带接入网网络优化方案

为了提高××电信宽带接入网网络质量,降低宽带用户,尤其是ADSL用户的故障申告率,根据省电信宽带接入网网络优化指导意见并结合××市宽带城域网网络现状,做出××电信宽带接入网络优化方案。     

社区宽带网络技术研究

社区宽带网络覆盖了接入网和用户驻地网的范围，向用户提供足以实现交互视频等应用的高速接入，它的技术实现手段有ＨＦＣ，ｘＤＳＬ，ＦＴＴｘ。     

论通信网的光纤接入技术

随着SDH技术和ATM技术的推广应用，我国的主干网基本实现了光纤化、宽带化，然而，当前接入网成为制约我国电信网宽带化的瓶颈。简单介绍了接入网，并对光纤接入技术进行了分析。     

光纤物理网的规划设计

目前运营商正积极推进接入网的建设以形成一个骨干网与接入网相匹配的大规模、高速率的整体宽带网络。本文就接入网中的光纤物理网在组网方式，纤芯分配等问题做一些探讨。     

Flexible Geschäftsmodelle in der Telekommunikation und die Netzneutralitätsdebatte

The net neutrality debate concerns the differential treatment of data on the Internet and the pricing models used by enduser internet service providers (IPSs). In particular, end-user ISPs may want to prioritize certain services and charge on the sender or the receiver side for this activity. In the policy debate it is asked whether regulatory intervention is warranted to restrict such behavior. The introduction of new end-user tariffs for fixed-line Internet access by Deutsche Telekom has heated up the debate in Germany. At the national level, the German Ministry of Economics and Technology has prepared a draft regulation on net neutrality, which aims at limiting the differential treatment of data transmission on the internet including the access networks and, thus, to protect the “Open Internet”. The European Commission has prepared an alternative draft regulation for a single European market in telecommunications, which contains provisions for an “Open Internet”. In this article, the authors investigate the extent to which the new tariff structure by Deutsche Telekom relates to the net neutrality debate. They also provide a first critical analysis of the proposals by the German Ministry of Economics and Technology and the European Commission.     

ICT,conflicts in financial intermediation and financial access: evidence of synergy and threshold effects

In this study we investigate the role of information and communication technology (ICT) in conflicts of financial intermediation for financial access. The empirical evidence is based on contemporary (or current values) and non-contemporary (or lagged by a year) quantile regressions in 53 African countries for the period 2004-2011. The main findings are: First, the net effect of ICT in formalization for financial activity in the banking system is consistently beneficial with positive thresholds. The fact that corresponding, unconditional and conditional effects are persistently positive is evidence of synergy or complementary effects. Second, the net effect of ICT in financial informalization for financial activity in the financial system is negative with a consistent negative threshold. Hence, the positive (negative) complementarity of ICT and financial formalization (informalization) is an increasing (decreasing) function of financial activity. Policy measures on how to leverage the synergy or complementarity between ICT and financial formalization in order to enhance financial access are discussed.     

Welfare and market-access effects of piecemeal tariff reforms on environmentally preferable products

We examine how welfare and market access are affected by piecemeal tariff reforms on environmentally preferable products (EPP) in a small open economy. We define EPP as clean goods that, when consumed, have no impact on pollution. First, we show that a uniform reduction of all tariffs improves welfare if a country’s imports consist only of clean goods. If a clean good is a net substitute for all other goods in excess demand, then reducing the highest tariff on the clean good improves welfare. Second, we show that a proportional tariff reduction leading to a welfare improvement also increases the value of imports if all tariffs are set at the same ad valorem rates. If the clean good is a net substitute for all other goods in excess demand, then reducing the lowest tariff on the clean good increases the value of imports. Finally, we explore the link between the change in welfare and the change in the value of imports in response to the tariff reforms, and we show that unlike a proportional tariff reduction, a tariff reduction on the clean good does not necessarily lead to improvements in both welfare and market access.     

“腾讯QQ”与“360”之争的反垄断法分析

“腾讯QQ”和“360”之争已广受国人关注,“腾讯QQ”的强制卸载行为更是将此风波推向极致。深层次分析“腾讯QQ”之行为,网络型产品自身的外部性特点使其具备市场支配地位的条件,数字的不可携带性是其滥用支配地位的根源,其强制绑架消费者利益,远超出了自力救济的范畴,违背了《反垄断法》的基本价值取向,严重破坏了正常的市场竞争秩序,这足以认定其实质上滥用了市场支配地位。针对“腾讯QQ”等新兴的网络型产业,适用《反垄断法》予以规制时面临相关市场理论缺失、滥用市场支配地位行为种类受限、市场份额并非界定市场支配地位的唯一标准等难题。因此,应完善相关反垄断法律制度,进一步明确网络型产业市场支配地位的特殊界定标准,进一步细化滥用市场支配地位的行为种类,引入网络强制接入机制,以保护消费者的利益,实现反垄断法保护竞争的基本价值取向。     

一种星地一体化路由设计的卫星IP网络

现有大部分支持IP的卫星系统只是提供一个连接地面路由器的物理通道,难以满足 宽带接入、多媒体服务以及星地网络一体化等新的需求。为此,提出了一个分组传输和交换 均 基于IP的GEO卫星系统,并从传输网络和路由结构两方面进行了描述。并针对星上资源紧张 的现状,采用了一种地面路由星上交换的新设计思路。通过星上IP交换可实现大量终端间的 单跳通信,一个可扩展的集中式IP路由结构可有效减少通过卫星的路由流量,使得通信效率 提高的同时,能实现卫星网络与Internet的无缝兼容。     

低净空钢桁梁特大桥承导线架设方法

通过包兰线包惠段巴彦高勒至杭锦旗区间上行线三盛公黄河特大桥接触网施工的工作实践,论述对低净空钢桁梁特大桥承导线架设施工方法、注意事项的一些看法,并提出如何在架线过程中避免对线索造成硬弯、损伤、扭面等质量缺陷,以便接触网施工人员参考。     

Firms’ export decisions—fixed trade costs and the size of the export market

This article presents a model of international trade under monopolistic competition. In the increasing returns sector firms face fixed, in addition to variable, trade costs, and both exporters and non-exporters may coexist. Exporters benefit from access to large foreign markets, thus a small country has a higher share of exporting firms than a large one. In contrast to standard models, the increasing returns sector will be more open in a small country than in a large one, and a small country may be a net exporter of such commodities, despite the disadvantage of a smaller home market.     

Household Economic Security and Public Policy

There are three challenges to household economic security: Slow income growth at the lower and middle parts of the income distribution, swings in households’ use of debt and leverage, and large numbers of households with low savings. Appropriate policy responses to these include increasing worker skills through greater opportunities for education and training, removing barriers to labor force participation, strengthening the safety net, improving access to credit while reducing exposure to harmful aspects of debt use, and making retirement savings easier and more automatic.     

Self-employment: the role of intellectual property right laws

Little is known about the impact of intellectual property rights (IPRs) on typically imitative self-employment. IPR laws have contrasting dual innovation creation and access effects on self-employment activity. The first effect is positive where strong IPR laws promote innovation and so create new opportunities for self-employment. The second effect is negative where strong IPR laws restrict access to innovation and technology used as inputs to self-employed businesses. Using a 33-country dataset over the period 1995?C2000, we estimate the impact of IPR laws on self-employment, helping to fill the vacuum of empirical evidence that has plagued policy decision making in this area. We find that patent activity has a negative effect on self-employment. However, overall, we find that more extensive and strong IPR laws have a net positive effect on self-employment activity.     

Liquidity constraints and the hedging role of futures spreads

This paper examines the behavior of the competitive firm under price uncertainty in general and the hedging role of futures spreads in particular. The firm has access to a commodity futures market where unbiased nearby and distant futures contracts are transacted. A liquidity constraint is imposed on the firm such that the firm is forced to prematurely close its distant futures position whenever the net interim loss due to its nearby and distant futures positions exceeds a threshold level. This paper shows that the liquidity constrained firm optimally opts for a long nearby futures position and a short distant futures position should the firm be prudent, thereby rendering the optimality of using futures spreads for hedging purposes. This paper further shows that the firm's production decision is adversely affected by the presence of the liquidity constraint. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:909–921, 2004