IP电话的实现及其关键技术

IP电话在推出后短短十年的时间以其低价、高效、灵活的特点迅速发展起来。本文介绍了IP电话的基本结构，比较了IP电话与普通电话的优缺点，讨论了IP电话的相关协议及关键技术，在这些基础上进一步指出IP电话的发展趋势，相信IP将成为未来信息通信的主导技术。     

奥地利移动通信市场

移动通信市场已经成为奥地利竞争程度较高的市场,主要的4家移动运营商分别是Mobilkom,Max.Mobil,Connect Austria和Tele.ring,其中Mobilkom占有的市场份额最大,奥地利政府于2000年11月拍卖了6张国内3G许可证,除了上述4家运营商获得3G许可证之外,奥地利Hutchison 3G和3G Mobile也得到了3G牌照.     

广西天等贫氧化锰矿石的选矿试验研究

天等锰矿石属高硅、低磷贫氧化锰矿石，矿物结晶粒度微细。选矿试验中进行了洗矿、强磁和重选流程研究，试验结果表明，洗矿效果较好，当原矿含锰１６．８５％，经一段洗矿后，可获得含锰２９．７７％，锰回收率为８６．２７％的锰净矿。     

利用低轨卫星星座的移动通信系统

本文介绍两种利用低轨地理卫星星座进行移动通信的系统。一种是英法联合研究提出的利用24颗低轨卫星组成的移动通信；另一种是美国研究提出的利用192颗低轨卫星组成的移动通信系统。最后将低轨卫星移动通信系统与同步卫星移动通信系统及高轨卫星移动通信系统进行了比较。     

A routing framework for providing robustness to node failures in mobile ad hoc networks

Nodes in a mobile ad hoc network are often vulnerable to failures. The failures could be either due to fading effects, battery drainage, or as a result of compromised nodes that do not participate in network operations. Intermittent node failures can disrupt routing functionalities. As such, it is important to provide redundancy in terms of providing multiple node-disjoint paths from a source to a destination. In line with this objective, we first propose a modified version of the widely studied ad hoc on-demand distance vector routing protocol to facilitate the discovery of multiple node-disjoint paths from a source to a destination. We find that very few of such paths can be found. Furthermore, as distances between sources and destinations increase, bottlenecks inevitably occur and thus, the possibility of finding multiple paths is considerably reduced. We conclude that it is necessary to place what we call reliable nodes (in terms of both being robust to failure and being secure) in the network to support efficient routing operations. We propose a deployment strategy that determines the positions and the trajectories of these reliable nodes such that we can achieve a framework for reliably routing information. We define a notion of a reliable path which is made up of multiple segments, each of which either entirely consists of reliable nodes, or contains a preset number of multiple paths between the end points of the segment. We show that the probability of establishing a reliable path between a random source and destination pair increases tremendously even with a small number of reliable nodes when we use our algorithm to appropriately position these reliable nodes.     

CDMA位置服务系统的本地定位平台建设

移动位置业务是移动通信网络的一项特色增值业务．将成为今后几年的业务增长亮点之一。中国联通总部的增值业务部于2002年采用集中设置方案，进行了CDMA位置服务系统一期工程的建设。本地定位平台建立于中国联通CDMA位置服务系统基础之上．其功能由以下的一项或多项组合而成：门户功能、中间件功能、GIS系统的的功能和对本地的CP进行管理和计费的功能。     

注高温热水管线缓蚀,阻垢实验研究

针对辽河油田高凝油区块注高温热水(85—95℃)引起的腐蚀、结垢,开展了室内和现场缓蚀、阻垢试验;分析了不同温度下注水的腐蚀情况,对比、考察了不同的缓蚀剂、阻垢剂及其复配物,得出了如下认识:在注高温热水条件下直接采用常温下使用的防腐蚀、防垢方法是不可行的,必须有针对性地进行高温条件下防腐蚀、防垢的实验研究工作。     

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四川目前生产的天然气中含硫天然气占７１％，而含硫天然气对高强度钻杆会产生硫化物应力腐蚀玻裂，因此，在含硫气井进行钻杆测试时，应重视钻杆的安全问题。文章探讨了高强度钻杆硫化物应力腐蚀玻裂的机理和影响钻杆脆断时间的各种因素，并提出在一定的条件下，高强度钻杆在含硫气并中进行测试是安全的。采用向钻杆内加缓蚀剂或内涂层钻杆，防硫油管测试，钻杆测试更加安全。建议继续开展高强度钻杆硫化物应力腐蚀玻裂时间的试验研究，以确定合理的钻杆测试安全时间。     

移动运营商渠道管理模式及存在问题分析

渠道作为营销体系中的重要一环，对移动运营商的发展起着举足轻重的作用。随着国内移动市场竞争的加剧，营销渠道的竞争将成为移动运营商间竞争的焦点。目前，国内两大移动运营商在渠道管理上存在诸多问题，从而影响了其市场拓展。分析了移动选营商渠道管理存在的三个较为突出的问题，并提出了可行的解决方法，从而为移动运营商的渠道管理工作提供思路。     

Using Automated Negotiation for Grid Services

The popularity of grid services has widened their application to numerous domains and increased the utilization of computational resources. In order to create more incentives for the resources owners to lease their resources and prevent users from wasting the resources, the introduction of a market-oriented grid is inevitable. However, the issues for the negotiation between service provider and consumer over the supply and demand of resources can be complex, with highly interdependent issues. In this research, a simulated automated negotiation mechanism including a co-evolutionary mechanism and a modified game theory approach is proposed, to assist them in reaching an agreement over the conflicting issues. In the proposed architecture, the co-evolution process is able to reduce the multiple dimensional search space into a two-dimension search space and identify the appropriate negotiation strategies for the negotiating agents to form a payoff matrix which can be used for the game theory related stage of their interaction. The multiple stage negotiation process is introduced to improve the negotiation result. In this paper, an application which requires a large amount of computational resources to process the data generated from mobile devises is used to demonstrate that the proposed system is able to resolve the conflicts and obtain a valid solution.