Ciao!

感谢四年朋友的陪伴

臭狗lzx看这👇

Email : Ping.Zhang@xjtlu.edu.cn
Office : EE222

Email: jie.zhang01@xjtlu.edu.cn
Office hours: 2:00-3:00PM, Tue & Wed EE522

lecture的简单笔记记录

Human-Centric Computing

The Design Life Cycle
It’s a interface/interaction design - an iterative process:
design –> implementation –> evaluation –> design

• not always start with design
  • maybe first figure out what people need/want (evaluation)
  • maybe there was an initial system (implementation)
• quite expensive having to re-implement a (complex) system over and over
• better strategies needed-ideas?
  • different types of “implementation”
  • different degrees of evaluation

为什么要有interface design process?

• to avoid user frustration with the finished product
• to avoid unnecessary costs during product development 减小产品开发过程中不必要的开销
• to avoid additional cost after product development 减小产品开发后的多余开销
• reasons for going over budget
  • user-requested changes
  • overlooked tasks
  • users did not understand their own requirements
  • insufficient user-developer communication and understanding

Foundations for designing interfaces

• Understanding users and their tasks
  • Task-centered system design
    • how to develop task examples
    • how to evaluate designs through a task-centered walk-through
• Designing with the user
  • User-centered design and prototyping
    • methods for designed with the user
    • low and medium fidelity prototyping
• Evaluating interfaces with users
  • the role of evaluation in interface design
  • how to observe people using systems to detect interface problems

Considerations when designing interfaces
do I know who my user and what their tasks are?

• how much computer knowledge?
• novice? occasional user? regular user? expert?
• what do people want to achieve, what are the tasks?

novel interfaces: what hardware I can expect?

Storyline Visualization
Design Principles

• D1 Lines in the same group should appear next to each other.
• D2 Otherwise, lines must be far away from each other.
• D3 A line must remain straight unless its group changes.

Optimization Goals

• reducing line crossings
• reducing line wiggles
• reducing white space

这周换一个方法记录blog，以记录自己想记录的东西为主。

在language的大集合里，有一部分语言被作为regular languages，测试他们是否是regular languages的方法是使用DFA & NFA & RL，pumpling lemma得出了有一部分语言是unregular的，unregular的语言不可以用DFA NFA Regular expression去define。这是就需要Grammar（content free grammar） which可以define regular languages and unregular languages

Content-free Grammar

G = (V, A, S, P)
V is a set of variables.
A is constant, terminates 阿尔法贝塔
S is a variable, state symoble
P is a set of rules (production) eg: x -> a a属于(VUA)^* 类似转移方程？
都是有限集
S –> aSb content-free意味着ab对S没有影响
L(G) = {w|wEA*, s->w}

1. Routing (2) - Distance vector algorithm
2. Intra-AS routing in the Internet: OSPF
3. Routing among the ISPs: BGP
4. The SDN control plane
5. ICMP
6. SNMP

这周的内容：

• UML类图
• 时序图
• 状态图
• 活动图

老师讲的ppt太寄了，建议自己学习。

Terms of packet in different layers

• Application layer: message
• Transport layer: segment
• Network layer: datagram
• Link layer: frame

TCP three-way handshake

• A -> B: SYN (seq = x, ack = 0, L = 0)
• B -> A: SYN ACK (seq = y, ack = x+1, L = 0)
• A->B: ACK (seq=x+1,ack=y+1,L=0)

Flow Control vs. Congestion Control

• Host vs. Router

这周还是继续IP的学习

Lecture

记虽然笔记迟了，但是一定会补回来呀！
这周第一部分是TCP congestion control。我有空再写笔记，我们先进入第二环节。也就是网络层 Network layer.

网络层服务

• 在发送主机和接收主机对之间发送段（segment）
• 在发送端把段封装到数据报（datagram）中
• 在接收端，将段上交给传输层实体
• 网络层协议存在于每一个主机和路由器（全部都有）
• 路由器检查每一个经过他的IP数据报头部