• If the expansion board is connected to the LED and the installation is normal, and then the USB cable is used to connect the power supply, the LED will light up, and the LED LCD screen will display; If not, it doesn't matter, we will continue to check the next serial port test;

Another example is that Alice and Bob write letters to each other, and the other receives them. In other words, Alice sends messages to Bob (push), and Bob receives them. This communication mode is SMTP.

We are already familiar with the image classification task, which is to classify the objects in the algorithm. And today we are going to learn about another problem of building neural networks, namely target detection. This means that not only do we have to use the algorithm to determine whether or not a car is in the picture, but we also have to mark its position in the picture and surround the car with a border or a red square, which is the object detection problem. In this paper, the basic knowledge of target detection algorithm for a brief review, to facilitate everyone...

Abstract: Communication technology is the foundation of the Internet of Things. If the Internet of Things is compared to the logistics system, then communication technology is equivalent to a variety of transportation methods to send express, such as air, water and land transportation. In the communication technology, generally it can be divided into two categories, one is wireless communication technology, the other is wired communication technology.

Usually when we need to access the hard disk data, the user process needs to use the kernel to access the hard disk data; Users tell the kernel to do something by calling system methods, such as read(), write(), and so on.

Purpose: Used to detect whether the network is smooth, and the network delay (work in ICMP protocol); The ability to display the amount of time in milliseconds between sending a request and returning a reply. If the reply time is short, it means that the datagram does not have to go through too many routers or networks and the connection speed is faster. Ping is similar to a test program. If run correctly, it can basically troubleshoot faults in the network access layer, the input and output lines, cables, and routers of the network card and MODEM.

SYN=1, SEQ = X, SYN=1, ACK = X +1, ACK = X +1, ACK = X +1, ACK = X +1, ACK = X +1, ACK = X +1, ACK = X +1, ACK = X +1 After receiving the response from the server, the client also needs to confirm the connection. Confirm that ACK is set to 1 in connection with seq = X +...

TCP Connection-Oriented (Guaranteed Link Establish Three Handholds) Reliable Delivery Full Duplex Oriented byte Streams Peer-to-Peer (and) eg File Transfer How does TCP achieve Reliable Transfer Stop Waiting Protocol A Round Trip Time ARQ Automatic retransmission request acknowledgement lost discarded repeat m1 retransmission acknowledgement m1 acknowledgement late received receive late acknowledgement do nothing improve pipeline continuous ARQ each time you need to wait for data to be received before moving the window move the past window...

TCP connection-oriented service in which a connection must be established before data can be transmitted and released after data transmission is complete. Therefore, TCP is a reliable transportation service, but because of this, it inevitably adds a lot of overhead, such as verification, flow control, etc. The corresponding application layer protocols are SMTP,TELNET,HTTP,FTP and so on. Each TCP connection has two endpoints. This breakpoint is called a socket...

Under Windows system, ipconfig with /all parameter, you can view the IP address, mask, default gateway, DHCP and DNS server and other information of the machine. On Linux or Mac systems, use the ifconfig command instead.