What does security engineering mean?

security means "safety protection". Security is a protective measure to meet the needs of its own security. Security engineering is the process of realizing security protection, and security products are the equipment serving security engineering. Security engineering includes building intelligence (building intercom, etc.), video monitoring, access control attendance, anti-theft alarm, fire sprinkler, computer room engineering, etc. Security monitoring system is a new specialty that people pay more and more attention to. As far as the current development is concerned, its application is getting wider and wider, and its technology content is getting higher and higher. Almost all high-tech can promote its development, especially the advent of the information age, which provides an opportunity for the development of this major. However, as far as the monitoring industry is concerned, the system composition has not been clearly divided, which makes it inconvenient for engineers and users to communicate when talking about security monitoring systems. For the security monitoring system, according to the different functions of each part of the system, we divide the whole security monitoring system into seven layers-presentation layer, control layer, processing layer, transmission layer, execution layer, support layer and acquisition layer. Of course, due to the increasing integration of devices, for some systems, some devices may exist in the system as multiple layers at the same time. First, the performance layer performance city is what we feel most intuitively, which shows the quality of the whole security monitoring system. Such as monitoring TV wall, monitor, high-pitched alarm horn, alarm automatic connection telephone, etc. all belong to this floor. 2. Control layer The control layer is the core of the whole security monitoring system, which is the most clear embodiment of the system's scientific and technological level. Usually we have two control methods-analog control and digital control. Analog control is an early control mode, and its console is usually composed of controller or analog control matrix, which is suitable for small local security monitoring system. This control mode has low cost and low failure rate. However, for medium and large security monitoring systems, this method is complicated to operate and has no price advantage. At this time, our wiser choice should be digital control. Digital control takes the industrial control computer as the control core of the monitoring system, which changes the complex analog control operation into a simple mouse click operation, shrinks the huge analog controller stack into an industrial control computer, and turns the complex and huge control cable into a serial telephone line. It turns medium and long-distance monitoring into reality and makes it possible for Internet remote monitoring. However, the digital control is not so perfect, and problems still exist, such as the high price of the control host, the waste of modules, the possible collapse of the whole system, and the lagging control. 3. Processing layer The processing layer may be called the audio and video processing layer, which distributes, amplifies, divides and so on the audio and video signals sent by the transmission layer, and organically connects the presentation layer with the control layer. Audio and video distributors, audio and video amplifiers, video splitters, audio and video switchers and other equipment all belong to this floor. 4. Transport layer The transport layer is equivalent to the blood of the security monitoring system. In small security monitoring system, our most common transport layer equipment is video cable and audio cable. For medium and long-distance monitoring system, we often use radio frequency cable and microwave. For long-distance monitoring system, we usually use the Internet as a cheap carrier. It is worth mentioning that the newly emerging transport layer medium-network cable/optical fiber. Most people have a misunderstanding in digital security monitoring. They think that the digital security monitoring system used by the control layer is the digital security monitoring system, but it is not. The transmission medium of pure digital security monitoring system must be network cable or optical fiber. When the signal comes out of the acquisition layer, it has been modulated into a digital signal. The digital signal runs on the mature network at present, which is theoretically lossless, which ensures the lossless display of remote monitoring images, which is incomparable to analog transmission. Of course, high-performance returns also require high-cost investment, which is one of the most important reasons why pure digital security monitoring systems cannot be popularized. 5. Execution layer The execution layer is the command object of our control instructions. In some cases, it is not well separated from the support layer and the acquisition layer mentioned later. We think that the controlled object is the execution layer equipment. For example: pan/tilt, lens, decoder, ball, etc. 6. Support layer As the name implies, the support layer is used to support the back-end equipment, protect and support the acquisition layer and the execution layer equipment. It includes support, protective cover and other auxiliary equipment. VII. Acquisition Layer The acquisition layer is the key factor for the quality of the whole security monitoring system, and it is also the place with the largest system cost. It includes lens, camera, alarm sensor and so on. The new development of transmission technology in security engineering Wireless video surveillance is accompanied by the beginning of 3G network coverage in China, the rapid development of COFDM, WIFI and other technologies, and the commercialization of satellites. With the further improvement of 3G-based wireless video surveillance, COFDM-based wireless video surveillance, WIFI-based wireless video surveillance, satellite-based wireless video surveillance and other technologies, wireless video services are further optimized in terms of bit error rate, switching efficiency, time delay and bandwidth stability. Wireless video surveillance will enter the era of rapid development. For a long time, video surveillance system has been mainly used to monitor and control important areas or remote locations. Video surveillance technology has also been more and more widely used in power systems, telecom rooms, factories, urban traffic, water conservancy systems, community security and other fields. The video monitoring system transmits the real-time video stream collected by the monitoring point to the monitoring center in real time, which is convenient for the monitoring center to conduct remote monitoring and timely command and handle emergencies. Video surveillance based on traditional wired network has obvious shortcomings. These shortcomings include: the distribution is limited, and the selection of monitoring points is generally near wired access points, which limits the flexibility of distribution; There is a large amount of work in distribution, so it is necessary to lay network cables and optical fibers. Because the amount of work in the basic network is often very large, general wired monitoring is more suitable for situations where the basic network already exists. The project cycle is long, and laying the basic network is time-consuming and labor-intensive; Lack of flexibility, inconvenient expansion and adjustment, will increase the amount of work and unnecessary basic network construction; Lack of mobility is a congenital defect of wired networks. In order to solve the above problems, wireless video surveillance came into being, so that video surveillance completely got rid of all kinds of restrictions caused by wired. It can be predicted that with the continuous progress of wireless video surveillance related technologies, such as terminal technology, networking technology and transmission technology, wireless video surveillance service will become one of the most typical applications of wireless network technology.