What are the network development technologies?
The technology of studying the general law and calculation method of network. Also known as the law of overall planning. Network technology is a technology that organically forms a task activity into a whole in the form of network graph, and obtains the optimal effect through analysis and calculation. It is an effective method to prepare the project speed plan and carry out scientific management on the plan. The basic method of network technology is network diagram, which is to make network diagram first, then optimize the project plan by using network diagram.
Network diagram is composed of four parts: process (arrow), node (circle), line, time parameter and time coordinate. Process refers to the process procedures such as material preparation in the project; Node is a symbol indicating the beginning, end or process boundary of the project, usually represented by a digital number in the circle, such as ① ②, etc; The line is the road organized by the process connected by sequence or logical relation, usually expressed by double real line or rough solid line; The time parameters are divided into two types: operation hours and node parameters. The former refers to the time consumed by the operation from start to completion, and is generally marked below the operation with the number word; Node parameters include node, early node and late section, and section early refers to the earliest start time. The latest time to start the work is the latest; The time coordinate is divided into cumulative date coordinate and calendar date coordinate, which is generally placed above or below the network diagram.
The steps of network drawing are as follows: ① decomposition engineering. ② List the operation. ③ Draw a sketch. ④ Calculate network time and sketch. ⑤ Find out the key lines (the lines that consume the longest time and determine the total project duration), and calculate the total construction period. ⑥ Adjust the layout configuration time coordinates.
The basic way to adjust and optimize network planning can be summarized as follows: to take time to key lines and resources to non critical lines.
The basic concept of multimedia technology
In the computer industry, media has two meanings: one is the carrier of information dissemination, such as language, text, image, video, audio, etc; The second is the carrier of storing information, such as ROM, ram, tape, disk, CD, etc. at present, the main carriers are CD-ROM, VCD, web page, etc. Multimedia is a new thing that has appeared in recent years, and is developing and perfecting rapidly.
The media in multimedia technology we mentioned mainly refers to the former, which is to use computer to digitize the media information such as text, graphics, images, animation, sound and video, and integrate it on a certain interactive interface, so that the computer has the ability to display different media forms interactively. It greatly changes the traditional way of people to obtain information, which is in line with the way people read in the information age.
Characteristics of multimedia technology
Multimedia is a human computer interactive information exchange and communication media which integrates more than two kinds of media, which has the following characteristics:
1. The diversity of information carrier: compared with computer, it refers to the diversity of information media;
2. The interaction of multimedia means that users can interact with various information media of computer, which provides users with more effective means to control and use information;
3. Integration refers to the computer-centered integrated processing of a variety of information media, which includes the integration of information media and the integration of devices dealing with these media.
Application of multimedia technology
In recent years, multimedia technology has been developed rapidly. The application of multimedia system has entered into various fields of human life with strong penetration, such as games, education, archives, books, entertainment, art, stock bonds, financial transactions, architectural design, family, communication, etc. Among them, the most widely used and the earliest is video games, millions of teenagers and even adults are fascinated by it, which can be seen the power of multimedia. Shopping malls and post offices are also an example of electronic shopping touch screen, which has greatly facilitated people's lives. In recent years, there are also teaching multimedia products, one-on-one professional professors, which has benefited many students. Because of this, many enterprises with vision have seen this form, and have used them to promote enterprises, even use their interactive ability to join e-commerce, self-service maintenance and teaching functions, which facilitate customers, promote sales, improve corporate image, expand business opportunities, and benefit from both sales and image.
It can be said that any enterprise with enterprising spirit cannot leave this latest high-tech product. First, the application of multimedia is very wide, destined to take root and blossom in all walks of life. Secondly, with the popularization of computers, the new generation of young people who grow up in the computer environment have become accustomed to this form. As a development oriented enterprise, they will not give up this future consumer. Third, because multimedia information technology has been very popular abroad, facing the increasingly international market, only to keep up with the international trend.
1. Multimedia introduction
The common computer application system can process information such as text, data and graphics. Besides processing the above information types, multimedia computer can also process image, sound, animation, video and other information comprehensively, which has ushered in a new era of computer application.
Multimedia has two main characteristics:
·Wide range of information: multimedia information includes audio and video information with the most intuitive and expressive power besides the conventional information types
·Interactivity: direct control of multimedia broadcast
The significance of multimedia technology application is as follows:
·It makes computer can process the most direct and common information in human life, which makes the application field and function of computer expanded greatly.
·It makes the human-computer interface and means of computer system more friendly and convenient, and non professional personnel can use and operate the computer conveniently.
·Multimedia technology makes the three information processing technologies, including audio-visual technology, computer technology and communication technology, closely combine, which lays a new foundation for the development of information processing technology.
Multimedia technology has been developing for many years. So far, the basic technologies of sound, video and image compression have gradually matured, and products have been formed into the market. Now popular technologies such as pattern recognition, MPEG compression and virtual reality are gradually becoming mature, and it is believed that it will enter the market soon.
2. Multimedia technology
Multimedia technology involves a wide range of areas, including:
·Audio technology: audio sampling, compression, synthesis and processing, speech recognition, etc.
·Video technology: video digitization and processing.
·Image technology: image processing, image, and graphic dynamic generation.
·Image compression technology: image compression, dynamic video compression.
·Communication technology: voice, video, image transmission.
·Standardization: multimedia standardization.
The following describes the development of main multimedia technologies.
2.1 audio technology
Audio technology has developed earlier, some of which have been mature and product-oriented a few years ago, and even entered the family, such as digital audio. Audio technology includes four aspects: Audio digitization, speech processing, speech synthesis and speech recognition.
Audio digitization is a mature technology. Multimedia sound card is designed by this technology. Digital audio also uses this technology to replace traditional analog mode and achieves ideal sound effect. Audio sampling includes two important parameters, sampling frequency and number of data. The sampling frequency is the number of sampling sound per second, the upper limit of human ear hearing is about 20kHz. At present, the commonly used sampling frequency is 11khz, 22khz and 44KHz. The higher the sampling frequency, the better the quality of sound, the larger the amount of data stored. The frequency of CD recording sampling is 44.1KHz, which has achieved the best hearing effect at present. The number of sampling data is the range of data representation of each sampling point. Currently, there are three kinds of data, which are 8-bit, 12 bit and 16 bit. Different sampling data bits determine different sound quality. The higher the sampling number, the larger the amount of data stored, the better the sound quality. CD record adopts 16 bit dual channel sampling, with a sampling frequency of 44.1KHz, thus reaching the professional level.
Audio processing includes a wide range, but the main aspects are focused on audio compression. The latest MPEG speech compression algorithm can compress the sound six times. Speech synthesis refers to the synthesis of text into language playback. At present, the synthesis level of several major foreign speech has reached the practical stage. Chinese synthesis has also made rapid progress in recent years, and the experimental system is running. The most difficult and attractive technology in audio technology is speech recognition. Although it is only in the experimental stage, it has been one of the hot spots in the research field because of its wide application prospect.
2.2 video technology
Although the development of video technology is short, the product application has been very large, and the products combined with MPEG compression technology have begun to enter the home. Video technology includes two aspects: video digitization and video coding.
Video digitization is a kind of digital signal which can be processed by computer through analog-to-digital conversion and color space transformation, which makes the computer display and process video signal. There are two kinds of sampling formats: y:u:v4:1:1 and y:u:v4:2:2. The former is the main format used by early products. Y:u:v4:2:2 format makes the color signal sampling double. The color, clarity and stability of video digitization have been improved obviously, which is the development direction of the next generation products.
Video coding technology is to encode digital video signal into TV signal, so it can be recorded in video tape or played on TV. Different technologies can be used for different application environments. From low-level game machine to television broadcasting level coding technology has been mature.
2.3 image compression technology
Image compression has always been one of the hot spots in technology, its potential value is quite large, and it is an important basis for computer processing of images and video and network transmission. Currently ISO has developed two compression standards, namely JPEG and MPEG. JPEG is a standard of static image compression, and it is suitable for continuous color or gray image. It consists of two parts: one is distortion free coding based on DPCM (spatial linear prediction), the other is distortion free algorithm based on DCT (discrete cosine transform) and Huffman coding. The former image compression has no distortion, but the compression ratio is very small. At present, the main application is the latter algorithm. The image has loss but the compression ratio is very large. When the compression is about 20 times, the distortion can not be seen.
MJPEG refers to motionjpeg, which uses JPEG algorithm to compress video signal at 25 frames / second speed to complete dynamic video compression.
MPEG algorithm is suitable for dynamic video compression. It not only encodes single image, but also uses the relevant principles of image sequence to remove the redundancy between frames, which greatly improves the compression ratio of images. Usually, the image quality is maintained and the compression ratio is up to 100 times. The disadvantage of MPEG algorithm is that the compression algorithm is complex and difficult to realize.
3. Multimedia product introduction
At present, there are many multimedia products in the market. The hardware products mainly include the following categories: sound card, voice synthesis card, CD-ROM, video card, video coding card, static image compression card, dynamic image compression card, etc. the software products include the production tools of multimedia application system, multi-media information consulting system, multimedia database, etc. When applying, the appropriate products are selected according to different requirements.
3.1 multimedia audio products
Sound card is one of the largest products in the market of multimedia products. Its main function is to store sound sampling into computer or turn digital sound into analog signal playing. Usually, it also has MIDI music synthesizer and CD-ROM controller. High-end products also have DSP device. The typical products of sound card are sound Ba card series.
In the aspect of speech synthesis card, Chinese composite card has been developed, which can synthesize the text into speech and play it. There is no mature product for speech recognition.
CD-ROM uses the same technology as laser record, which can store sound, image and other information into CD for access. It has a large capacity and no wear in use, and has become one of the important products of multimedia. At present, the development of Mo technology has produced high-speed CD-ROM drive, which has a wide application prospect. The biggest market for applications is now CD-ROM programs.
3.2 multimedia video and compression products
Video card can convert TV video signal into digital signal, and display it on VGA after superimposing with VGA signal. At the same time, it can capture video image storage disk or small window semi dynamic continuous tools, which can make application development get rid of programming problems of programming and many multimedia products. MIS (Information Management) system has been widely used in computer applications. The development of multimedia technology has made the development of multimedia MIS system a reality. At present, multi media can easily make powerful multimedia application system without writing programs.
The application prospect of industries such as transportation tourism and information consultation in professional fields is also quite broad