Sampling Given a continuous time waveform, can we represent it using discrete samples? How often should we sample? Can we reproduce the original waveform?

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

一、联立方程模型随机误差项方差—协方差矩阵 二、三阶段最小二乘法简介 三、完全信息最大似然法简介

L Translation(30%) PartI(10%) 1. Will you please send us a copy of your catalogue and current price-list for bicycles? We are interested in bicycles for both man and woman, and also for children. We are the leading bicycle dealers in the city, where cycling is popular, and have branches in five neighboring districts. If the qual ity of your bicycles is satisfactory and the prices are reasonable, we will place regular orders for fairly large numbers 2. Multimedia software is used for electronic publishing and electronic games and in employee training programs, The term multimedia is also used to describe home entertainment systems and other

Cytoplasmic Membrane System or Cytomembranes Internal Membrane or Endomembrane System(EMS) Includes: nuclear envelopes, endoplasmic reticulum (ER), Golgi complex(GC), lysosomes and a variety of vesicles or vacuoles. Although each of these membranous organelles has its own distinct structure