Technology for meteorological, military and aerospace industries; Remote sensing is a comprehensive measurement technology, which uses sensors to receive electromagnetic wave information radiated by high-altitude or distant objects, and prompts the nature, shape and changing trend of the measured objects through processed or recognizable images or recording tapes used by computers. It is mainly used in meteorology, military affairs, aerospace and other fields. With the rapid development of electronic technology, the computing tools urgently needed by military and scientific research have also been greatly improved. 1946, eckert and Moses of the University of Pennsylvania developed the world's first electronic computer. The innovation of electronic components and materials further promotes the development of electronic computers in the direction of miniaturization, high precision and high reliability. In the 1940s, scientists discovered semiconductor materials and used them to make transistors instead of electron tubes. 1948, shockley, Badin and Bratin of Bell Laboratories invented the transistor, so transistor radios, transistor televisions and transistor computers quickly replaced various vacuum tube products. 1959, kilby and Noyce of the United States invented integrated circuits, and microelectronics technology was born. LSI was born in 1967. More than 1000 transistor circuits can be integrated on a silicon wafer the size of a grain of rice. 1977, American and Japanese scientists made VLSI and integrated130,000 transistors on a 30-square-millimeter silicon wafer. Microelectronics technology has greatly promoted the upgrading of electronic computers, making them show unprecedented information processing functions and become an important symbol of modern high technology. In order to solve the problem of resource sharing, stand-alone computers have rapidly developed into computer networking, realizing data communication and data sharing between computers. Communication media has developed from ordinary wires and coaxial cables to twisted pair, optical fiber lines and optical cables; The input and output devices of electronic computers have also developed rapidly. Scanner, plotter, audio and video equipment, etc. Make the computer more powerful and can handle more complex problems. With the rise of multimedia technology in the late 1980s, computers have the ability to comprehensively process various forms of information, such as words, sounds, images, movies, etc., and are increasingly becoming the most important and essential tool for information processing. At this point, we can preliminarily think that information technology (IT) is a comprehensive technology based on microelectronics and photoelectric technology, supported by computer and communication technology, and with information processing technology as the theme. The close combination of electronic computer and communication technology marks the arrival of the digital information age. Intetnet is the largest computer network in the world, which originated from ARPANET, a computer experimental network supporting military research, and was developed by the Advanced Research Projects Agency (ARPA) of the US Department of Defense in 1968. The original intention of ARPANET is to help researchers working for the US military exchange information through computers. Its design and implementation are based on a leading idea: the network should be able to withstand the test of faults and keep working normally. When a part of the network loses its function due to attacks, other parts of the network can still keep normal communication. In the early 1990s, with the development of WWW, the Internet gradually moved towards civilian use. Because the good interface of WWW greatly simplifies the difficulty of Internet operation, the number of users has increased dramatically. Many government agencies and commercial companies are aware of the great potential of the Internet, so they join the Internet in large numbers. In this way, the number of points on the Internet has greatly increased, and the information on the Internet is varied and colorful. Nowadays, the Internet has penetrated into all aspects of people's lives. People can get the information they need in time through WWW browsing and e-mail. Internet has greatly facilitated the dissemination of information and brought people a brand-new way of communication. It can be said that the Internet is another revolution in human communication after the invention of telegraph and telephone. The development of Internet in China is relatively late, but it is still relatively rapid. Research on Computer Application in Beijing from 65438 to 0987
The hospital took the lead in opening the X.25 line to Germany. Since then, China Academy of Sciences, Tsinghua University and Peking University have all established their own campus networks, and realized the connection with the Internet. On this basis, the Internet in China has begun to take shape. In recent years, the Internet has developed rapidly, covering 65,438+054 countries, including China. 1994, there was only one international export of Internet in China, with more than 300 users. By 65,438+0996, it has developed into 7 international export lines with more than 20,000 users. By 1995, four backbone networks have been initially established in China: China Education and Research Internet (CERNET) operated by Tsinghua University. Supported by Ministry of Electronics, Ministry of Electric Power and Ministry of Railways, China Jinqiao Information Network (CHINAGBN) operated by Jitong Company. China Network (Chinanet) established by the Ministry of Posts and Telecommunications. Chinanet is the first commercial network in China. The first phase of the project was completed in June, 1995, and two international export lines with a bandwidth of 64Kbps were opened in Beijing and Shanghai. It is estimated that after the completion of the second phase of the project, it will cover the backbone networks of all provinces and cities in China, and the bandwidth of export lines will be increased from 64K to 2 M. CHINANET has covered 3/kloc-0 provinces and cities in China, with an international dedicated line of 86Mbps. The establishment of the above four backbone networks has laid a good foundation for the use and development of the Internet in China, and I believe that the Internet will have a bright future in China.