安全防火墙的设计

文章主要讨论了防火墙设计的安全策略以及国外产品的最新性能比较。     

公安部信息系统安全产品质量监督检测中心通过的许可销售产品(防火墙类)

┏━━━━━━━━━━┳━━━━━┳━━━━━━┳━━━━━━━━━━━━┓┃ 公司名称 ┃许可证号 ┃有效期至 ┃ 产品名称 ┃┣━━━━━━━━━━╋━━━━━╋━━━━━━╋━━━━━━━━━━━━┫┃广州市众达迅通技 ┃ ┃ ┃ ┃┃术有限公司 ┃XKC33010 ┃ 20010419 ┃天网防火墙Verl 0 ┃┣━━━━━━━━━━╋━━━━━╋━━━━━━╋━━━━━━━━━━━━┫┃北京诺方信息技术 ┃ ┃ ┃鑫城服务器端安全网 ┃┃有限责任公司 ┃XKC3301 1 ┃ 20010504 ┃ ┃┃ ┃ ┃ ┃关Verl.1 ┃┣━━━━━━━━…     

分布式防火墙思想在移动IP安全中的应用

移动IP具有广阔的发展前景,但是安全问题成为当前商业应用的主要障碍.本文提出一个新的安全模型来解决移动IP的安全问题.模型借鉴了分布式防火墙的思想,具有很强的实用性,能够系统的解决移动IP的安全问题.     

Motorola半导体事业拟将独立

Motorola公司关于半导体事业部门的独立问题经过4个月的调研,已于9月把独立的方案提交给了董事会。独立的好处之一是半导体事业的股票可以公开上市。但这两件事要分别获得董事会和美国证券交易委员会的批准,并须看定股票交易市场的时机上市,故独立的具体日期尚未肯定。半导体事业独立之后,Motorola将集中经营通信和综合电子产品。反观近5年公司半导体事业部的业绩,1998~2000年间微有增长,从73.1亿美元、73.7亿美元,增长到78.8亿美元,但2001年受半导体业大不景和分立器件分离出去,成立On-Semiconductor公司的巨大影响,公司半导体营收剧降33…     

Firewalling the Net

To connect any stand-alone enterprise network to the Internet in a safe and secure manner, it is necessary to erect a firewall at the interface between the internal and external networks. We review the current state of firewall technology and describe the principles behind the solutions that are being adopted by BT. We also describe how companies are presently utilising the bandwidth of the Internet to extend their internal intranets using cryptographic techniques and indicate some of the directions in which firewall research will be going in the next few years.     

Mobilising the Net

Bringing the Internet and mobile communications together, as service providers and manufacturers are now doing, will create a new mass medium for communication, interaction and transaction along with a high-volume industry supplying the associated infrastructure. A combination of technologies is creating a direct evolutionary path from today's low-bandwidth mobile connections and limited text messaging to full scale Internet access via mobile networks. Bandwidths of up to 2 Mbit/s, available through UMTS, will allow the most demanding of today's Internet applications to be carried out using portable devices. Some of the applications of this combined technology, the portable devices and the media processors are described in this paper     

Running off the rails

High-speed rail works well in Europe and Japan, so why can't the United States get it right? The outlines the problems faced by railways in the US, highlighting the case of Amtrak's Acela Express fleet which were taken out of service after only twenty months due to a major fault; 200 comparatlively minor defects were also identified. One of the main reasons for the problems with railways in the US Northeast corridor is that a new dedicated track alignment was not possible and speed restrictions are in force in densely populated regions. In retrospect, some problems were to be expected, considering that an unproven advanced-technology train was being introduced on an existing, if upgraded, infrastructure. Despite these teething troubles, Acela Express is a success. The Northeast corridor is the proving ground for high-speed rail in North America, from both technical and marketing perspectives. For the sake of sustainable mobility in an environmentally acceptable manner, high-speed rail must be the way forward in North America,.     

Empire off the grid

Dean Kamen, arguably the world's most famous living inventor, is in his favorite place. It's the basement of the main house on his private island, a pristine concrete bunker outfitted with a command station that can monitor and control all aspects of the production and consumption of electric power on the island. The island, off the coast of Connecticut, is called North Dumpling Island, but Kamen, who invented the Segway and is something of an eccentric, calls it the Dumplonian Empire. He, of course, is Lord Dumpling.     

Opening the Mobile Net

iPhone hackers, spectrum auctions, new carrier technology might doom mobile network carriers' "garden wall" restrictions on consumer choices.     

9月网事·网人·网语

刚刚过去的这个9月,中国的互联网界可谓热力难挡。两大盛事接踵而至:前有官方主持的2005 中国互联网大会,各界群英齐聚京城,“拓展区域合作,把握产业机遇”;后有失约一年的“西湖论剑”广发英雄帖,刚刚并购雅虎中国的新阿里巴巴“帮主”马云春风得意,     

PDP巨头反击与LCD争夺市场份额

Market leader Matsushita Electric Industrial Co. （Panasonic） and Hitachi Ltd. announced an agreement to supply each other with giant plasma panels for televisions. Starting in fiscal 2007, Matsushita will supply Hitachi with 103-inch panels, and in fiscal 2008, Hitachi will reciprocate by supplying Matsushita with 85-inch panels.     

自动制造系统Petri网模型的资源变迁网性质分析

资源变迁网NR是自动制造系统Petri网模型N的简化形式,在系统死锁的分析与控制中有重要作用.文中总结了资源变迁网的若干性质,并指出:对于任意一个非空资源子集R1,若资源变迁网NR关于R1的内连子网N1=NR[R1 ∪('R1 ∩ R1')]是强连通的,则一定存在以R1为资源集的资源变迁回路,特别地,θ=就是其中一个.进一步,若θ又满足完美条件,则θ即为N的一个完美极大资源变迁回路.     

移动网与广电网互联互通付费系统的探讨

探讨了移动网与广电网通信中的付费系统。首先概述了移动网与广电网通信的发展趋势,提出了两大网络通信而带来的核心———付费系统研究的重要性,然后对该付费系统的设计思想进行了分析,并提出了相应的物理结构、付费模式和所需要满足的系统功能。     

一种基于Petri网的监控视频事件抽取方法

通过扩展Petri网定义,提出了一种监控视频事件时空关系和逻辑关系的描述方法,通过将语义级的查询事件映射成Petri网,再在Petri网推理过程中结合计算机视觉算法对场景运动目标行为的解释,实现了有关运动目标行为的事件抽取和相应监控视频片段的定位.     

RS-485网络设计降低功耗问题

本文主要讨论在ＲＳ－４８５网络设计中,如何在保持良好的传输特性的同时降低率损耗。     

摘去西方理论的光环

企业所有的策略和方法都必须建立在现实条件的基础上,而不要被那些宏大的、看似严谨的、成体系的管理理论吓住。我们万不要因为读了几本管理巨著,就认为“站得高,看得远了”,就可以不尊重事实了。     

侧蚀对脊形掺铒光波导放大器净增益的影响

用有限元方法分析了脊形掺铒Al2O3光波导放大器内部信号光和泵浦光的电磁场模式分布,结合速率方程和传输方程,数值模拟了脊形Er∶Al2O3光波导放大器的净增益特性,讨论了光波导侧蚀对放大器净增益的影响.