无线接入技术分析

首先介绍了无线接入的四种方式,在此基础上具体分析了宽带无线固定接入技术LMDS、宽带IP无线移动接入技术和基于蓝牙技术的两种无线接入技术,并给出了无线接入网的几种实现方案.     

无线局域网接入机制效率的分析研究

随着便携式计算机(包含笔记本和PDA)的快速普及,无线局域网IEEE 802.1 1成为目前短距离无线通讯技术的主流.无线局域网IEEE 802.11中采用DCF、PCF的接入机制,IEEE802.11e中采用EDCF、HCF的接入机制.对这四种接入机制的接入效率和服务质量 (QoS)进行分析,在此基础上提出了两种改进接入效率的方式,即碰撞导向工作模式与工作站数量导向工作模式.通过这两种方式使网络资源的分配更具有弹性,并满足具有不同优先级的工作站对效率的需求.     

再探滑动变阻器

滑动变阻器在高中电学计算中占有很重要的地位,它的存在往往导致电路问题的难度提升了一个台阶,所以了解滑动变阻器的不同接入方式在电路中的作用对提升解决电路问题的能力十分重要。滑动变阻器在电路中有四种接入方法,其中限流和分压接法在很多参考书籍中被提及,与之相关的规律,教师、学生也已耳熟能详。但另两种接法因其规律复杂,     

H3C无线智能终端识别技术助力高校网络安全

一、智能终端识别技术的产生 随着高校无线网络的逐步建设,覆盖范围以及使用人群的扩大,无线不再仅仅是一种简单的接入方式,其核心应该是可以随时随地使用任何设备,不论是自己的还是学校提供的设备接入校园网络。这必将带给学校网络“四多”的变化：     

Flash动画在PowerPoint中几种接入的探讨

几乎每种软件都能调用一种或多种其它媒体软件,且彼此间留有一种或多种接入方式,但并非每种接入方式都是理想的。选用合理的接入方式,是使用者非常关心的问题。该文系统讨论了在PowerPoint制作的课件中,接入Flash动画的多种方法,并对各种接入方式适用的条件、特点及需要注意的问题等几个方面做出了阐述,以便选择应用。     

中小型内部网基于电话双绞线的接入方式

本为中、小型单位提供了三种Internet接入方案。即DDR接入、ISDN接入和ADSL接入，分析了三种接入方式的特点，提供了软、硬件解决方案。     

论 ADSL 宽带网接入技术

ADSL 是一种较为实用的小区宽带网接入方式。本文通过把 ADSL 宽带网接入技术与其它几种宽带接入技术的鲜明对比,把 ADSL 宽带网接入技术的特点和情况作了简捷的阐述。     

三相四线有功电能表不接零线所造成的影响

本文通过对三相四线有功电能表在不同方式运行中的计量分析,可以知道接入零线与未接零线在运行中出现同样故障时,其计量的误差不同,会造成计算错误。所以在安装时一定要求接入零线。     

一种小型局域网络接入Internet的方法

由 3～ 1 0台微机相互连接起来构成的局域网络称为小网 ,它可用于一般办公室或家庭 .小网中微机数量较少 ,结构简单 .随着 Internet的普及 ,小网也面临着如何接入 Internet的问题 .微机接入 Internet一般有 3种方式 ,即专线方式 ,拨号方式和接入局网方式 .专线方式接入速度快 ,但费用高 ,对一般办公室或家庭都不合适 .拨号方式较为灵活 ,易于实现 ,但因需给每台微机配置调制解调器和电话线 ,故接入费用和上网费用均较高 .接入局网方式连接简单 ,费用最低 ,但必须依托已经入网的局域网 ,故其局限性较大 ,不易普及 .这些方式对小网来说都不…     

嵌入式Internet技术的分析与研究

本文对嵌入式Internet技术原理与嵌入式Internet技术方案进行了分析,讨论了实现嵌入式Internet的几种方案,然后重点阐述了嵌入式Internet的几种接入方式,并对这几种接入方式进行了比较,指出了各自的优缺点。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.