Abstract: A method of registering a reference image includes obtaining information of layers in a design pattern that is used for forming an actual pattern on a substrate and comparing the information to obtain a difference therebetween. The method further includes obtaining a reference image for testing the actual pattern based on the difference. Thus, the reference image, which is obtained from the design pattern, but not from the actual pattern, may include information on all of the actual patterns on the substrate.

Abstract: In an Ethernet passive optical network (EPON) system and a method for traffic scheduling in the EPON system, the method comprises: dividing a periodic transmission cycle between an optical line termination (OLT) and an optical network unit (ONU) for upstream traffic time band assignment into an Expedited Forwarding (EF) sub-cycle preset for EF traffic and an Assured Forwarding (AF) sub-cycle dynamically set for AF and BE traffic; dynamically assigning, by means of the OLT receiving ONU queue length information from the ONU, a first AF sub-cycle band using the queue length information and the preset EF sub-cycle band; and granting to the ONU, by means of the OLT, a first preset EF sub-cycle band, the dynamically assigned first AF sub-cycle band, and a second preset EF sub-cycle band. Thus, EF traffic band assignment for the next cycle is performed one cycle in advance, thereby reducing idle time and significantly enhancing overall bandwidth efficiency.

Abstract: A method and an apparatus for supporting error cause of network management system are for exchanging an error cause defined by a different standard between a manager and an agent, especially when a present error status cannot be defined by error causes defined by SNMP (Simple Network Management Protocol) standard. The SNMP agent receives an SNMP message from the manager under Get/SetRequest command, and analyzes the received SNMP message to compare and find out whether or not a normal execution is possible. If it turns out that the normal execution is possible, the SNMP agent executes an internal command, and transmits a response message thereof to the manager. However, if it turns out that the SNMP message is abnormal, the SNMP agent first compares and finds out whether the abnormal SNMP message can be represented by one of SNMP standard error causes.