Attention deficit disorder is disability

1. The privacy computing of ant chain integrates the privacy computing and the digital identity and authorization system of blockchain, and builds three sets of hard core privacy confidential platforms suitable for multi application scenarios - Moss multi-party security computing platform, ant chain data privacy service platform and data flow security management and control platform, Solve data security compliance, privacy controllable security issues. I'm glad that you have been able to take my answer and hope to help you all the time

2. Question:
can I apply for a disability certificate for attention disorder
answer:
attention deficit can't apply for disability certificate
disability certificate is the legal certificate to identify the disabled and their categories and grades. At present, there are seven types of disabilities in China: visual disability, hearing disability, speech disability, physical disability, intellectual disability, mental disability and multiple disabilities. All disabled persons who meet the disability standards of the second national sample survey of disabled persons shall be issued with a disability certificate.

3. untrue! If you have any questions, please ask

4.

The realization of global universal digital currency does not depend on the level of science and technology, but on political influence

In fact, the US dollar has the characteristics of super sovereign currency, and it has the status of circulating currency in many countries, but the US dollar has not been digitized

However, when the tide is approaching, we should not discuss whether it is Libra or bitcoin, but whether it is digital US dollar or digital RMB

5. EtherCAT EtherCAT technology breaks through the system limitations of other Ethernet solutions: through this technology, there is no need to receive Ethernet packets, decode them, and then the process data to various devices. EtherCAT slave device processes Ethernet frame when the message passes through its node: FMMU (field bus storage management unit) embedded in each slave reads the corresponding addressing data when the frame passes through the node, and transmits the message to the next device at the same time. Similarly, the input data is inserted into the message when it passes by. In the whole process, the packet has only a few nanoseconds delay. The main station is also very economical. The commercial standard NIC or any Ethernet controller integrated on the main board can be used as the hardware interface. The common feature of these interfaces is that the data is transferred to PC through DMA (direct memory reading), that is, the network reading does not need to occupy CPU resources. Protocol EtherCAT protocol adopts official Ethernet type in Ethernet frame. With this Ethernet type, the control data can be transmitted directly within the Ethernet frame without redefining the standard Ethernet frame. The Ethernet frame can be composed of multiple subpackages, each subpackage serves a specific memory area of the logical process image area, which can reach up to 4GB. Data sequence is independent of physical sequence, so the addressing of Ethernet terminal mole can be sorted at will. Broadcast, multicast and communication between slave stations can also be realized. When the EtherCAT component runs in the same subnet as the master controller, or when the control software reads the Ethernet controller directly, the Ethernet frame can be used to transmit data directly. However, EtherCAT is not limited to single subnet applications. EtherCAT UDP encapsulates EtherCAT protocol as UDP / IP data packet, which means that any control of Ethernet protocol stack can be programmed into EtherCAT system, and even communication can be connected to other subnets through router. In this case, the system performance obviously depends on the real-time performance of the controller and its Ethernet protocol. The response time of the EtherCAT network itself is almost unaffected: UDP frames only need to be unpacked at the first site. Performance EtherCAT brings the network performance to a new level. With the help of the FMMU in the slave node and the direct memory access of the master station of the network controller, the process of the protocol is completely completed in hardware. The whole process of the protocol is implemented in hardware, so it is completely independent of the real-time running system, CPU performance or software implementation of the protocol stack. The update time of 1000 I / OS is only 30 s. A single Ethernet frame can exchange 1486 bytes of process data at most, which is equivalent to 12000 digital inputs and outputs, and the transmission time of these data is only 300 S. the communication of 100 servo axes is only 100 s. During this period, the system updates the actual positions and states of all axes with command values and control data, and the distributed clock technology makes the synchronization deviation of axes less than 1 microsecond. Even if this performance is guaranteed, the bandwidth is still sufficient for asynchronous communication, such as TCP / IP, downloading parameters or uploading diagnostic data. The ultra-high performance EtherCAT technology can realize the control idea that the traditional fieldbus system can't reach. For example, Ethernet systems can now handle not only speed control, but also current control of distributed drives. The huge bandwidth can realize the simultaneous transmission of each data information and its status information. EtherCAT adapts the communication technology to the super computing power of modern instrial PC. the bus system is no longer the bottleneck of the control concept. The distributed I / O interface may run faster than most local I / O interfaces. EtherCAT replaces PCI. Because the motherboard integrates Ethernet card, the slot used for interface card is no longer necessary. With the rapid development of PC components towards miniaturization and economy, the volume of instrial PC increasingly depends on the number of slots. The bandwidth of Fast Ethernet and the process data length of EtherCAT communication hardware provide new possibilities for the development of this field: the traditional interface in IPC can now be transformed into an integrated EtherCAT interface terminal. In addition to addressing distributed I / O, it can also address drive and control units, as well as composite systems such as fieldbus master station, fast serial interface, gateway and other communication interfaces. Even other Ethernet device variants without protocol restrictions can be connected through distributed switch port devices. Because one Ethernet interface is enough to meet the communication requirements of the whole peripheral equipment, it not only greatly simplifies the volume of IPC host, but also reces the cost of IPC host. Topology EtherCAT supports almost any topology type, including line type, tree type, star type, etc. The bus structure or linear structure named after fieldbus can also be used for Ethernet, and is not limited by the number of cascaded switches or hubs. The most effective method of system connection is the combination topology of linear, branch or tree cross structure. Because the required interface already exists in many devices such as I / O mole, there is no need to add a switch. Of course, the traditional Ethernet based star topology can still be used. Different cables can also be selected to enhance the flexibility of connection: the flexible and economical standard class 5 Ethernet cable can use 100base-tx mode or e-bus (LVDS) to transmit signals. Plastic encapsulated optical fiber (PFO) can be used in special applications. It can also realize the complete combination of different Ethernet connections (such as different optical fiber and copper cables) through switches or media converters. According to the requirements of distance, the physical layer of Fast Ethernet or e-bus can be selected as the physical medium. Fast Ethernet physical layer allows the maximum cable length between two devices to be 100 meters, while e-bus can connect up to 10 meters. Since the number of connected devices can be as high as 65535, the capacity of the network is almost unlimited. Accurate synchronization of distributed clock is particularly important for distributed processes with simultaneous actions. This is true, for example, when several servo axes perform coordinated motion at the same time. The most effective synchronization method is to precisely arrange the distributed clock (refer to IEEE 1588 standard [6]). Compared with the case that communication failure will immediately affect the synchronization quality in fully synchronous communication, distributed clocks have excellent fault tolerance for the related fault delay that may exist in the communication system. With EtherCAT, data exchange is based on pure hardware mechanism of "parent" and "child" clock. Due to the logical ring structure (with the help of the physical layer of full plex Fast Ethernet), the master clock can simply and accurately determine the delay offset of each slave clock propagation. Distributed clocks are adjusted based on this value, which means that a very accurate, less than 1 microsecond, deterministic synchronization error time base can be used within the network. In addition, high-resolution distributed clock can not only be used for synchronization, but also provide accurate local time information of data acquisition. When the sampling time is very short, even if there is a very small instantaneous synchronization error of position measurement, it will lead to a large step change in speed calculation. For example, the speed of position calculation of motion controller through sequential detection is just like this. In EtherCAT, the time stamp data type is introced as a logical extension. The huge bandwidth provided by Ethernet enables the high-resolution system time to be linked with the measured value. In this way, the accurate calculation of speed is no longer affected by the synchronization error of communication system, and its accuracy is higher than that of communication measurement technology based on free synchronization error. Hot connection hot connection function can connect all parts of the network and decouple or reconfigure freely; The flexible response features provided by the system change the requirements of many applications that need to change the I / O configuration at runtime. For example, processing center with change characteristics, tool system equipped with sensors, or intelligent transmission equipment, flexible workpiece actuator, etc. EtherCAT system takes these requirements into account: arbitrary configuration. EtherCAT function security traditionally, the security function is independent of the automation network, using special hardware or special security bus system. EtherCAT security function enables security related communication and control communication to be realized on the same network. The security protocol is based on EtherCAT application layer without affecting the underlying operation. It is certified by IEC61508 standard and meets SIL 3. Data length is variable, so it can be used in security I / O and security servo drive technology. Like other EtherCAT data, security data can be transmitted without using security router or gateway. Procts that fully comply with EtherCAT functional safety certification have been launched. The safety over EtherCAT protocol conforms to the fscp 12 (functional safety communication equipment specification) in IEC 61748-3 standard. Open EtherCAT technology is fully compatible with Ethernet and truly open. This protocol can coexist with other Ethernet protocols that provide various services, and all the protocols coexist in the same physical medium, which usually only has a small impact on the performance of the whole network. A standard Ethernet device can be connected to an EtherCAT system through a hub terminal that does not affect the cycle time. The equipment equipped with traditional fieldbus interface can be integrated into the network through the connection of EtherCAT fieldbus master terminal. UDP variants allow devices to be integrated into any slot interface. EtherCAT Technology Group ensures that each interested organization can implement and use the network. EtherCAT protocol will be released after the final technical specification.

6. It depends on the quality of the cable you buy.

amp can reach 300m

others can reach 120m

7.

1、 1. Disability: [C] á n j í ]

defects of limbs, organs or their functions: ～ children. The leg is not cured. It falls

2 à ng à I]

A, blocking the road, so that it can not pass smoothly; Obstacles: ～ objects

B. things blocking the progress: exclude ～. Clean up

Mental retardation and inability to take care of themselves

3. Defect: [Qu] ē xi à N]

deficiency or incompleteness: physiology ～

Disability: Zheng Guanying's "Shengshi Weiyan · school": "all the deaf and disabled people have learned to learn one art to support themselves."

Obstacles: Wei Wei's opening up the golden age of China: "all difficulties will be overcome; All the forces that hinder our progress will be shattered. "

However, the existence of bourgeois ideology, the existence of certain bureaucratic styles in state institutions, and the existence of defects in certain links of the state system are in contradiction with the socialist economic foundation

Third, the use of different objects

disability focuses on body defects, such as hand and foot diseases, eye and ear diseases

disorders focus on brain intelligence

defects focus on the loss of physical function or incomplete play, such as stuttering, poor motor balance and so on

The four and three connections all have the meaning of physical disability

8. Ethernet (Ethernet)
Ethernet was first established by Xerox, and was developed as a standard by Dec, Intel and Xerox in 1980. Ethernet is the most widely used LAN, including standard Ethernet (10Mbps), fast Ethernet (100Mbps), Gigabit Ethernet (1000Mbps) and 10G Ethernet. They all conform to IEEE802.3 series standards
(1) standard Ethernet
at the beginning, Ethernet only had the throughput of 10Mbps. It used the access control method of CSMA / CD (Carrier Sense Multiple Access with collision detection), which is usually called standard Ethernet. Ethernet mainly has two kinds of transmission media, that is twisted pair and coaxial cable. All Ethernet networks follow the IEEE 802.3 standard. The following are some Ethernet standards of IEEE 802.3. In these standards, the first number represents the transmission speed, and the unit is "Mbps", the last number represents the length of a single network cable (the base unit is 100m), base means "baseband", and broad means "bandwidth"
· 10BASE-5 uses thick coaxial cable, the maximum network segment length is 500m, and the baseband transmission method is adopted
· 10base-2 uses thin coaxial cable, the maximum length of network segment is 185m, and the baseband transmission method is adopted
· 10Base-T uses twisted pair cable, and the maximum network segment length is 100m
· 1base-5 uses twisted pair cable, the maximum network length is 500m, and the transmission speed is 1Mbps
· 10broad-36 uses coaxial cable (rg-59 / u CATV) with a maximum length of 3600m, which is a broadband transmission mode
· 10base-f uses optical fiber transmission medium with transmission rate of 10Mbps
(2) Fast Ethernet
with the development of network, the traditional standard Ethernet technology has been difficult to meet the increasing demand of network data flow speed. Before October 1993, only fiber distributed data interface (FDDI) was available for LAN applications requiring more than 10Mbps data flow, but it was a very expensive LAN based on 100Mbps optical cable. In October 1993, Grand Junction company launched the world's first fast Ethernet hub fastswitch 10 / 100 and network interface card fastnic100, and the fast Ethernet technology was officially applied. Then Intel, synoptics, 3Com, baynetworks and other companies have launched their own fast Ethernet devices. At the same time, IEEE802 Engineering Group also studied various standards of 100Mbps Ethernet, such as 100base-tx, 100base-t4, MII, repeater, full plex and so on. In March 1995, IEEE announced the IEEE 802.3u 100Base-T Fast Ethernet standard, which started the era of Fast Ethernet
Fast Ethernet has many advantages compared with FDDI which used to work under 100Mbps bandwidth, mainly reflected in that fast Ethernet technology can effectively guarantee the investment of users in the implementation of cabling, it supports the connection of type 3, 4, 5 twisted pair and optical fiber, and can effectively use the existing facilities
in fact, the deficiency of Fast Ethernet is also the deficiency of Ethernet technology, that is, fast Ethernet is still based on carrier sense multiple access and collision detection (CSMA / CD) technology. When the network load is heavy, the efficiency will be reced. Of course, this can be made up by switching technology
100Mbps Fast Ethernet standard is divided into three sub categories: 100base-tx, 100Base-FX and 100base-t4
· 100base-tx: it is a fast Ethernet technology using class 5 data level unshielded twisted pair or shielded twisted pair. It uses two pairs of twisted pairs, one for sending and one for receiving data. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. According to eia586 class 5 Wiring Standard and IBM SPT class 1 wiring standard. Use the same RJ-45 connector as 10base-t. Its maximum network segment length is 100 meters. It supports full plex data transmission
· 100Base-FX: it is a fast Ethernet technology using optical cable. It can use single-mode and multi-mode optical fiber (62.5um and 125um) to connect the maximum distance of 550m. The maximum distance of single-mode fiber connection is 3000 meters. 4b / 5B coding mode is used in the transmission, and the signal frequency is 125MHz. It uses mic / FDDI connector, St connector or SC connector. Its maximum network segment length is 150m, 412m, 2000m or longer to 10km, which is related to the type of optical fiber used and working mode. It supports full plex data transmission. 100base FX is especially suitable for the environment with electrical interference, large distance connection, or high security environment
· 100base-t4: it is a fast Ethernet technology that can use 3, 4 and 5 kinds of unshielded twisted pair or shielded twisted pair. It uses four pairs of twisted pairs, three pairs for data transmission and one pair for collision detection. 8B / 6T coding mode is used in the transmission, and the signal frequency is 25MHz, which conforms to eia586 structured wiring standard. It uses the same RJ-45 connector as 10Base-T, and the maximum length of network segment is 100m
(3) Gigabit Ethernet
with the in-depth application and development of Ethernet technology, enterprise users have higher and higher requirements for network connection speed. In November 1995, IEEE802.3 working group appointed a high speed study group to study how to increase the speed of Fast Ethernet to a higher level. The research group studied the feasibility and method of increasing the speed of Fast Ethernet to 1000Mbps. In June 1996, IEEE Standard Committee approved the Gigabit Ethernet project authorization request. Subsequently, the IEEE 802.3 working group established the 802.3z Working Committee. The purpose of ieee802.3z committee is to establish Gigabit Ethernet standard, including full plex and half plex operation at 1000Mbps communication rate, 802.3 Ethernet frame format, carrier sense multiple access and collision detection (CSMA / CD) technology, one repeater in a collision domain, multi access and collision detection The downward compatible technology of 10Base-T and 100Base-T Gigabit Ethernet has the characteristics of easy transplantation and management of Ethernet. Gigabit Ethernet is flexible in dealing with new applications and new data types. It is an extension of the successful 10 Mbps and 100 Mbps IEEE802.3 Ethernet standards, providing a data bandwidth of 1000 Mbps. This makes Gigabit Ethernet a strategic choice for high-speed, broadband network applications< At present, there are mainly three technical versions of 1000Mbps Gigabit Ethernet: 1000base-sx, - LX and - Cx. 1000base-sx series adopts compact disc (CD) or VCSEL (vertical cavity surface emitting laser) transmitter with low cost and short wave; The 1000base-lx series uses relatively expensive long wave lasers; 1000base-cx series intends to connect high-performance servers and high-speed peripherals with short jumper cables in the wiring room< (4) 10G Ethernet
now the standard of 10Gbps Ethernet has been formally formulated by IEEE 802.3 working group in 2000. 10G Ethernet still uses the same form as previous 10Mbps and 100Mbps Ethernet, which allows direct upgrade to high-speed network. The frame format, full plex service and flow control mode of IEEE 802.3 standard are also used. In half plex mode, 10G Ethernet uses the basic CSMA / CD access mode to solve the conflict problem of shared media. In addition, 10G Ethernet uses the same management objects as Ethernet defined by IEEE 802.3 group. All in all, 10G Ethernet is still Ethernet, just faster. However, e to the complexity of 10G Ethernet technology and the compatibility of the original transmission medium (at present, it can only be transmitted on the optical fiber, which is not compatible with the twisted pair commonly used by the original enterprises), and the high cost of this kind of equipment (generally $20000-90000), this kind of Ethernet technology is still in the primary stage of research and development, and has not yet been applied.

9. Instrial Ethernet is a powerful area and unit network based on IEEE 802.3 (Ethernet). Universal compatibility allows users to seamlessly upgrade to new technologies. At the beginning of Ethernet, the throughput of Ethernet was only 10 Mbps. This early 10 Mbps Ethernet was called standard Ethernet. The difference is that one is fast and the other is slow