computer learning books

needs to adjust the size of the sub-network.Note: In this way the subnet is divided into subnets, all 0 subnets, and all 1 subnets are available.CIDR (No-class inter-Domain routing protocol):The non-class inter-domain routing protocol allows multiple classes to be merged into a larger network, called a hyper-net.For example, the 192.24,8.0~192.24.15.0 these 8 have a class network, you can synthesize a network number of 192.24.8.0, the subnet mask is 255.255.248.0.CIDR can significantly reduce t

tail is the frame delimitation (that is, determining the bounds of the frame).Each link layer protocol specifies the maximum length of the data portion of the frame that can be transmitted-the MTU of the largest transmission unit(Maximum Transfer unit).?When the data is a text file consisting of printable ASCII code, a special frame delimiter can be used for frame delimitation.(ASCII code is 7-bit encoding, can be combined into 128 different ASCII code, which can be printed 95, and non-printabl

formula:– The maximum data transfer rate for a channel with limited bandwidth and noise interference. –C = W log2 (1+s/n) (BITS/S)• W is the channel bandwidth (in Hz);• S is the average power of the signal transmitted within the channel;• N is the Gaussian noise power inside the channel. s/n commonly used decibels, 1 decibels =10lgs/n5. Data encoding Technology(1) Pulse code modulation pcm--analog data to digital signaloperation: Sampling, quantization, encodingApplication: Voice digitization(2

the operating system.2.5 VGA (video Graphic Array)The display of the graphic image, focusing on the resolution and color concentration, each image display color will occupy memory, video card above the capacity of a memory flicker. Video card communicates with CPU and memory via North BridgeGraphics Specifications PCI---> AGP----> PCIE2.6 HDD InterfaceHda generally refers to the IDE interface of the hard disk, HDA generally refers to the first hard disk, similar to the HDB,HDC, etc.SDA generall

instruction of one process and the instruction of another process are interleaved.ThreadsA process can consist of multiple threads, each running in the context of a process and sharing the same code and global data.Virtual MemoryVirtual memory is an abstract concept that provides an illusion for each process that each process seems to be using main memory exclusively. Each process sees a consistent memory, which is the virtual address space. The address in the figure is increased from bottom to

1_5Traceroute, a command tool, you can see the network internal information, ISP internal information.1_6Understand the modular package of the network. Learning protocols and layers, this construction computer the key mechanism of networks. The package is the lower the protocol the more encapsulated outside, forming a protocol stack. Each layer is in the message plus its own header. When browser and server

This article summarizes the image storage format that I understand.The data in the computer is binary, so the picture is no exception.This is a description of the OpenCV document, which is stored in the code using a matrix.Similar is (BGR format):The smallest unit of the picture is the pixel, here is the BGR (usually the notation of blud, Green, and red) that represents each pixel corresponding to the value (here BGR the mixture, can get all the value

| | _inf = Max |x_i|$General P norm:| | x| | _p = (\sum_{i=1}^n x_i^p) ^1/p$Matrix norm:| | a| | _f = \sqrt{\sum_{i=1}^m \sum_{j = 1}^n a_ij^2 = \sqrt{tr (a^ta)}$The rank of the matrix: $det (AB) = det (BA) $ $det (a^-1) = \frac{1}{\det (A)}$ $det (a^t) = det (A) $ $det (A) = 0$ when and only if $a$ is singular Trace of the Matrix: the and of the diagonal elementsSpecial matrices: Identity matrix: The diagonal element is 0 and the other element is 1 Diagona

useful solutions. The solution is given only when the recursion is reached at the lowest level, and then the solution is slowly given by recursive regression steps. (contains a certain abstract meaning)2. In the process of "governance" is also "with the first step • The absolute trust", the direct treatment of the solution to calculate.3. The entire process and the "factorial" recursion is basically the same, just a lot of "points" of the procedure.4. If it is not the problem of the binary tree

called when the main window is loaded to initialize the operation such as the following cases: You can initialize the maximum minimum value for the set form, and so on. private void Form1_Load (object sender, EventArgs e){This. MinimumSize = this. Size;This. MaximumSize = this. Size;This. MaximizeBox = false;} 2. Create a new form Sometimes we need a function, click on the menu and then pop up a new window. The Name property of Window 2 is: Formdisplay At this poin

operationResource management functions: Process management, memory management, device management10. Events that cause process creationUser login, job scheduling, service delivery, application request11. Events that cause the process to block and wake upFailed to request shared resource to SystemWait for some sort of operation to completeNew data not yet arrivedWaiting for new tasks to arrive12, the synchronization mechanism should follow the rulesIdle let inBusy is waitingLimited waitThe right

In vs2013, you can write programs for Windows Phone 8.1, but you need to use the Windows-brought virtual machine Hyper-V for debuggingThe genuine system will not have a problem when you turn on Hyper-V, but a pirated system can cause system instability and even crash, and I happen to have windowsphone8.1 's cell phone, so I'm thinking about debugging a phone program with a real machine.Asked the teacher, the teacher told me to use remote debugger this plugin, but I did not succeed after a few at

My computer learning experience in the past four years The last time I talked about a large project in the organization, this project made me enter the field of software project management for the first time. The project team is composed of three technical staff from the three companies, A third-party project manager is also hired for management. The three companies were divided into various groups, respons

ReferencesMask R-CNNMask R-CNN DetailedOpen Source code: tensorflow version code link ; keras and TensorFlow version code link ; mxnet version code link First, MASK-RCNNMask R-CNN is an instance segmentation (Instance segmentation) algorithm, which can accomplish various tasks, such as target classification, target detection, semantic segmentation, case segmentation, human posture recognition, etc. by adding different branches, which is flexible and powerfu

Objective: To identify numbers 0-9 Using KNN Material: 32*32 digital square arrays (saved as text files) #-*-Coding: UTF-8-*-from numpy import * def img2vector (filename): # generate a 1*1024 array (zeros is a numpy function, as for the differences between array and list, we will not introduce them here.) returnvect = zeros () # use the open function to open a text file Fr = open (filename) # cyclically read the file content for I in range (32): # Read a row and return the string linestr = Fr.

When creating a window drawing in it, you must also specify the coordinate system to be used and how to map the prepared coordinates to pixels (x * Y) on the physical screen ). The window is measured physically by the number of records. Before painting, you must specify "how to convert a specified coordinate pair to screen coordinates, specify the trim area first (specify the area occupied by the window in the Cartesian coordinate system ). 1. in two-dimensional space, the trim area is the

. GOOGLE. COM. GitHub.com mail is handled by 1 Aspmx.com.$ host Facebook.github.comfacebook.github.com is an alias for github.fastly.net . Github.map.fastly .net has address 103.245 222.133 hostCommands can also be used for reverse queries, that is, querying a domain name from an IP address, equivalent to dig -x . 192.30.252.153153.252.30.192.in-addr.arpa domain name pointer pages.github.com. (2) nslookup commandnslookupCommands are used to interactively query a doma

source host uses the destination host's IP address to query the destination host's physical address.The Physical address is encapsulated in the frame header of the datagram. The typical physical address is the MAC address in Ethernet. MAC address in two places makesUse: The network card in the host is sent to itself by the destination MAC address in the header, and the switch in the network makesUse the destination MAC address in the header to determine which port the datagram is forwarded to.

One, download driver installation, 1, manually open the CH341 folder (within the driver folder), double-click the installation driver2, Nemo m3s development hardware settingsThe hardware needs to do the following 2 points:1, USB plug USB1 (COM), turn on the power switch J14 (blue and white switch), and install the driver2, boot boot jump cap insertion position, BOOT1 set 0,boot0 settings 0,j15 position, positive look, jumping caps are inserted in the lower end.3. Use FLYMCU to download(1) First

for the + all numbers to find out [ -3,34,3.2345] equivalent to + do the delimiter #We just need to add all the elements in it.ret = Re.finditer ('-?\d+\.? \d*', expression) sum=0 forIinchRet:sum+=Float (i.group ())returnstr (SUM)#3, first remove all the parentheses in the calculation of its resultsdefremove_bracket (expression): whileTrue:#Get rid of all the parentheses first.Express_a_bracket = Re.search ('\([^()]+\)', expression)ifExpress_a_bracket:#handle this expression with onl