what is cv?
cv是计算机视觉，是关于如何计算机能够理解图像和视频的学科，通过计算机模拟人的视觉系统。
cv refers to computer vision, a science field about how computer can understand images and videos, about how computer can imitate human visual system.
what is nlp?
nlp指的是自然语言处理，是关于如何计算机能够理解人类语言并加以分析提取信息的学科。
nlp refers to nature language process,?a science field about how computer can understand human language and analyze human language to get useful information.
what is ai and ml?
ai指的是人工智能，是一门关于计算机如何像人一样自动解决问题的学科。ml指的是机器学习是ai的一个子集，是关于如何机器可以通过经验来自动优化的学科。
ai refers to artificial intelligence, a science field about how computer autpmatically solve problems like human. ml refers to mechine learning, a subset of ai about how computer can automatically improve algorithm through experience.
what is recursion?
递归指的是程序运行时会自己调用自己。
recursion refers to that a procedure?will invoke iteself during running time.
what is iteration?
迭代指的是程序重复一个过程，一次执行的输出是下一次执行的输入。
iteration refers to procedure repeating a process and the outcome of the next execution is input of this execution?.
what is linked list and array?
链表就是通过指针串在一起，没有连续存储的数据列表。数组是按顺序存储的数据列表。
linked list is?a kind of data list which linked by pointer and donnot orderly stored in memory while array is sore in order in memoey and supprot random search.
what‘s the?difference between c++ and c?
c和c++有着相同的语法。c是c++的子集，c++在c的基础上增加了面向对象功能并且有了更好用的标准模板库，方便了使用。
c and c++ share the smae syntax. c is subset of c++. c++ add object-oriented programming and stl, which make is easier to use.
whats the difference between parallel and concurrent?
并行就是事情同时发生，并发就是事情在同一个时间段发生，并不一定同时，但用户看来可能还是同时的。
parallel

is multi events occur in the same time. concurrent is multi events occur in a small range of time but not really in the same time, but it looks like paarallel from the perspective of viewer.
what is process and what is thread?
进程是程序运行起来的实例，进程包含代码和活动;线程是轻量级的进程，进程是资源分配的最小单位，线程是cpu调度的最小单位。
proces is instance of a running program and include code and its activity. thread is light process. process is the smallest unit of resource allocation and thread is the smallest unit of cpu allocation.
what is deadlock?
死锁就是不同进程同时占有资源和申请资源，导致有一些进程运行不了的情况。
deadlock is a situaion that because processes possess resource and ask for resource in the same time,?some processes cannot proceed. we can solve this problem by deadlock prevention, deadlock detection, deadlock avoidance, deadlock recovery.（死锁四大条件是：互斥、不可剥夺、请求与保持、循环等待）
?what is virtual memory?
虚拟内存就是通过将外存的一部分逻辑上视为内存来拓展可使用内存的大小。
virtual memory logically view part of?external memory?as internal memory to extend the storing space of internal memory.
what is tcp/ip?
tcp/ip协议是传输控制协议和因特网协议。tcp协议工作在传输层，是用来建立可靠连接传递数据的。ip协议工作在网络层，是用来传递分组的。
tcp/ip refers to transmission control protocol and internet protocol. tcp works on transmission layer, which is used for building connection and transmission.ip works on network layer, using for datagram delivery.
what is dns?
dns指的是域名系统，用来将域名转换为对应的ip地址，有递归转换和迭代转换两种方式。
dns refers to domain name system, which can translate domain name into?ip address. dns have two approach to find ip address :recursion and iteration.
what is ip adress and how do these ip address classify?
ip地址是用来唯一表示网络中设备并且能够定位设备的数字串。ip地址分为abcde，a类前8位是网络号后24位是主机号，b类前16位是网络号后16位是主机号，d类前24位是网络号后8位是主机号，e类用来多播。
ip address is?a sequence of number which is used to identify a device in network and locate this device. ip adress can be classified into class a ,class b,class c and?class d. the first 8 bits of class a ip address is network id and the next 24 bits are host id. the first 16 bits of class b ip address is network id and the next 16 bits are host id.the class c ip address is used for multicast.
what is http?
http指的是超文本传输协议，使用户可以访问各种类型资源，http的产生是为了html服务的，后者称为超文本标记语言提供了一种创建网页的方法。
http refers to hypertext transfer protocol, making user access to various resource. the birth of http server for html, which refers to hypertext markup language, which provides a method to create web pages.
how?dose tcp establish connection?
tcp establishs connection through three handshakes.?the first handshake: a sends connection requests to b. the second hankshake: b allocate cache and send acknowledgments to a. the third hanshake: a allocate cache and send acknowledgments to b and begin to send data to b.
how dose tcp end connection??
tcp end connnection through four handshakes. the first handshake: a sends connection release to b. the second handshake: b sends acknowledgment to a and after that, b keep sending data untill all data have been sended. the third handshake b sends connection release to a. the fourth handshake a sends?acknowledgment to b.