Abstract:
PURPOSE: A method for generating a multicast LLID(Logical Link ID) in an EPON(Ethernet Passive Optical Network) is provided to assign a proper LLID to multicast traffic, and to receive the multicast traffic in an EPON, then to apply a multicast group member to the EPON, thereby performing an address filtering process in an application layer. CONSTITUTION: A mapper(110) of an OLT(Optical Line Terminal)(100) inserts a multicast address into a hash function, forms the inserted multicast address in 14 bits, and uses the multicast address as contents of an ID field of an LLID(300). The mapper(110) of the OLT(100) uses the rest 2 bits as multicast mode bits with unicast. If the OLT(100) transmits the generated multicast LLID(300) to ONUs(Optical Network Units)(110-n), emulation layers(206) of the ONUs(110-n) perform filtering processes by seeing the multicast LLID(300) transmitted from the OLT(100).
Abstract:
PURPOSE: A redundant system and method for a GE-PON(Gigabit Ethernet Passive Optical Network) and a frame structure for controlling the same are provided to achieve the path transfer between an OLT(Optical Line Terminal) and a 2xN splitter and to control the path transfer. CONSTITUTION: An ONU(Optical Network Unit) checks a signal environment and detects an SF/SD. The ONU generates an OAM(Operation, Administration, and Maintenance) frame for a transfer request according to a checked result and transmits a packet, including the OAM frame, to an OLT. The OLT receives the packet and detects the transfer request. In response to the transfer request, the OLT transfers the present working path to a protection path and transfers the protection path to the working path.
Abstract:
PURPOSE: A method for additionally registering ONUs(Optical Network Units) in a GE-PON(Gigabit Ethernet Passive Optical Network) and an Ethernet frame structure are provided to offer an additional ONU registration method required for the embodiment of GE-PON in a PON structure. CONSTITUTION: An OLT(Optical Line Termination) downlinks normal frames to a plurality of registered ONUs in order to provide a bandwidth allocation request opportunity to them(300). Each ONU uplinks a bandwidth allocation request frame at the bandwidth allocation request start point of the next cycle. The OLT collects bandwidth allocation requests from the registered ONUs(302), and executes scheduling for the requested bandwidths using a scheduler(304). Then the OLT compares BW_tot, a total available bandwidth, with BW_alloc, an allocation-requested bandwidth(306). If the difference between BW_tot and BW_alloc is larger than 208us(308), the OLT downlinks a grant frame for additional registration(312). Then, after waiting during the time of registration offset + frame time + slot position + down-stream delay time, the OLT judges whether a registration request frame is received(316).
Abstract:
PURPOSE: An apparatus for transforming acceleration is provided to generate energy for moving an object in a simple way by causing changes of acceleration. CONSTITUTION: An apparatus for transforming acceleration comprises first to third rotors(42,43,44); a plurality of arms(50,51,54) having ends connected to the rotors through rotating shafts(45,48,49) and the other ends connected with each other so that the arms are movable by being interlocked with the rotation of the rotors; and a weight(55) arranged on the arm, which generates a centrifugal force in the direction different from the direction of the centrifugal force generated by the rotation of the rotors. The first rotor rotates, and the second rotor and the third rotor are engaged with the outer surface of the first rotor and rotate relatively to the rotation of the first rotor.
Abstract:
PURPOSE: A wafer stage of exposure equipment is provided to improve productivity by removing generation of a local focus due to contamination of a wafer. CONSTITUTION: A wafer clamping apparatus(100) is formed with an up/down robot(110) and a couple of clamping robots(120). The up/down robot(110) is used for lifting a wafer(W) from a transferring arm to a clamping position. The clamping robots(120) are used for grasping an edge of the wafer(W) of the clamping position. The clamping robot(120) is formed with a driving portion(122), a shaft(124), and a clamp ring(126). The shaft(124) is moved to a front or a rear direction by the driving portion(122). The clamp ring(126) is installed at one end of the shaft(124) in order to grasp the edge of the wafer(W). The driving portion(122) can be formed with a cylinder.