Source coding Source Encode Channel Alphabet alphabet Source symbols Letters of alphabet, ASClI symbols, English

Channel Coding When transmitting over a noisy channel, some of the bits are received with errors Example: Binary Symmetric Channel (BSc) Pe= probability oferror Q: How can these errors be removed? A: Coding: the addition of redundant bits that help us determine what was sent with greater accuracy

Modulation Representing digital signals as analog waveforms Baseband signals Signals whose frequency components are concentrated around zero Passband signals Signals whose frequency components are centered at some frequency fc away from zero Baseband signals can be converted to passband signals through modulation Multiplication by a sinusoid with frequency fc Eytan Modiano

Used for analyzing network performance In packet networks, events are random Random packet arrivals Random packet lengths While at the physical layer we were concerned with bit-error-rate, at the network layer we care about delays How long does a packet spend waiting in buffers?

Routing Must choose routes for various origin destination pairs o/d pairs) or for various sessions Datagram routing: route chosen on a packet by packet basis Using datagram routing is an easy way to split paths Virtual circuit routing: route chosen a session by session basis Static routing: route chosen in a prearranged way based on O/D pairs Eytan Modiano

Packet Multiple Access SHARED UPLIN TERMINAL APPL TERMINALL TRANS NET LLC DLC MAC

1、20世纪70年代以前,投资银行经历了漫长的产生和早期发 展过程。1929年以前是投资银行产生及持续发展的阶段; 19291933是投资银行膨胀及动荡的阶段。大量的商业银行 和投资银行倒闭;1933年《格拉斯—斯蒂格尔法》颁布以 后,美国的商业银行和投资银行开始实行分业经营,投资银行 进入新的发展阶段

1.什么是财务报表?企业为什么需要编制财务报表? 2.财务报告包括那些内容?试结合美国财务会计准则委员会的论述加以说明。 3.资产负债表的基本构成是什么?它的主要用途何在? 4.什么是收益表?多步式收益表的功能是什么?请自己选择一家上市公司的收益表加以说明

布鲁金斯学会主席,美前总统经济顾问委员会主 席奥肯(Arthur Okun)根据美国1947-1960年 的数据,得到如下回归方程,称之为奥肯定律 y

一、填空题 (一)试题 1.篮球运动是由美国()州()学院体育教师()博士发明的。 2.初试时期的篮球活动,是取材于民间儿童将()投掷到()中去的游戏,而逐渐完善形成篮球运动