How to quickly and accurately detect the error of NC machine has become a hot issue for domestic and foreign scholars. Based on GPS principle, a laser tracker is adopted the multi-station and time-sharing measurement to rapidly and accurately detect the geometric accuracy of NC machine. The machine is controlled to move in the preset path, and a laser tracker is used to measure the same motion trajectory of the machine successively at different base stations. The position of base station and the space coordinates of measuring points can be determined based on large amount of measured data.
WLANs Terrestrial microwave — Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes.
Terrestrial microwaves are in the low gigahertz range, which limits all communications to line-of-sight. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals. Cellular and PCS systems use several radio communications technologies.
The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
Radio and spread spectrum technologies — Wireless local area networks use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area.
Free-space optical communication uses visible or invisible light for communications. In most cases, line-of-sight propagation is used, which limits the physical positioning of communicating devices. The use of spread-spectrum or OFDM technologies may allow users to move around within a local coverage area, and still remain connected to the network.
Products using the IEEE Fixed wireless technology implements point-to-point links between computers or networks at two distant locations, often using dedicated microwave or modulated laser light beams over line of sight paths.
It is often used in cities to connect networks in two or more buildings without installing a wired link. Wireless ad hoc network[ edit ] A wireless ad hoc network, also known as a wireless mesh network or mobile ad hoc network MANETis a wireless network made up of radio nodes organized in a mesh topology.
Each node forwards messages on behalf of the other nodes and each node performs routing. Ad hoc networks can "self-heal", automatically re-routing around a node that has lost power. Various network layer protocols are needed to realize ad hoc mobile networks, such as Distance Sequenced Distance Vector routing, Associativity-Based RoutingAd hoc on-demand Distance Vector routingand Dynamic source routing.
These networks can be used to connect branch offices of business or as a public Internet access system. The wireless connections between access points are usually point to point microwave links using parabolic dishes on the 2. A typical system contains base station gateways, access points and wireless bridging relays.
Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photovoltaic solar panels or wind systems they can be stand alone systems.
In a cellular network, each cell characteristically uses a different set of radio frequencies from all their immediate neighbouring cells to avoid any interference. When joined together these cells provide radio coverage over a wide geographic area.
This enables a large number of portable transceivers e.
Although originally intended for cell phones, with the development of smartphonescellular telephone networks routinely carry data in addition to telephone conversations: The GSM network is divided into three major systems: The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred to where it needs to go.
GSM is the most common standard and is used for a majority of cell phones. Sprint happened to be the first service to set up a PCS. The newer GSM networks are replacing the older system.The working principle of the wireless system is introduced, and a series of experiment is set up to calibrate the system accuracy and to measure the cutting temperature of the rotating work piece.
The experimental results show that the wireless system has a satisfactory reliability and temperature measurement accuracy.
Wi-Fi is a wireless Communication technology include devices with Wi-Fi card receiving transmitted and Received radio signals from antennas through routers. Working Principle: Wi-Fi is a high speed internet connection and network connection without use of any cables or wires.
You can now generate a system within Resorts, library. Wireless Net Neutrality Regulation and the Problem with Pricing: An Empirical, Cautionary Tale " Id. Net-work neutrality principles have already made inroads into mobile communications regulation in the formulation of the January , MHz spectrum auction, which includes "open communications transport system, it is the "last-mile.
The Principles of Network Security Design Figure 1 – Defense-in-Depth principle: protection of IT They should be installed in the net-work path between potential threat sources and sensitive IT system resources.
When designing IPS systems, attacks Principle of least privilege IT system subjects (e.g., users, administrators) should have.
A wireless network or Wireless Local Area Network (WLAN) serves the same purpose as a wired one — to link a group of computers. A wireless network or Wireless Local Area Network (WLAN) serves the same purpose as a wired one — to link a group of computers. Because "wireless" doesn't require.
Principle of Wireless Net Work System. Principle of wireless network system The principle of wireless network system needs the tool to transmit and expand the signal or we call “Access Point” and it has PC Card.
It is a LAN Card that use to connect to Access Point. It also use radio wave to transmit & expand the signal.