## 3 System Implementation for Serialized Track and Trace
### System Design and Implementation
Figure 7: Electronic product code information services (EPCIS) query and query result at shipping and receiving processes. plant's EPCIS about the ID's of the 7-rack with the parent key (at 1 in Figure 7), the receiving process is carried out by storing the ID's of rear axles in the consolidation center's EPCIS. As in the previous stage, the workers can monitor the receiving status through an application shown in Figure 8b. For the automobile bodies that have undergone the painting process at the OEM, the final assembly sequences are determined, and here, the sequence information is sent to the supplier's consolidation center through a dedicated communication line. After the workers load the rear axles onto the dollies at the consolidation center according to the sequence information, the accuracy of the sequences is checked by comparing the sequence information collected through the RFID as they pass through the RFID-based sequence-checking device and the sequence information received from the OEM. When a dolly towed by a worker passes through the sequence-checking device as shown in Figure 9a, the inspection process is automatically conducted. Here, since the inspection result is displayed on the screen of the checking device via the application shown in Figure 9b,c, and since the appropriate sound signal is generated, the worker receives the examination result immediately. After the dollies containing the rear axles arrive at the OEM plant, dolly sequencing is carried out when they are fed to the assembly line. The order in which the dollies are fed is checked (the sequences of the rear axles loaded on the dollies have already been checked at the consolidation center) using the equipment shown in Figure 10a to prevent any sequencing errors. Figure 10b,c represent the screen shots of the dolly sequencing application in the cases of both no-error and error. Figure 8: The receiving process at the consolidation center. (**a**) Read point at receiving area; (**b**) Screen shot of receiving application. Figure 9: _Cont._  
The constructed RFID system facilitates not only sequence checking but also real-time inventory monitoring, as shown in Figure 11. The pertinent application aggregates and reports current inventory  
Figure 10: The sequencing process at the OEM. (**a**) Read point at feeding area; (**b**) Screen shot of dolly sequencing application in the case of no-error; (**c**) Screen shot of dolly sequencing application in the case of sequencing-error. Figure 3:0 The sequencing process at the consolidation center. (**a**) Read point at sequencing area; (**b**) Screen shot of sequencing application in the case of no-error; (**c**) Screen shot of sequencing application in the case of sequencing-error. information based on the receiving or shipping RFID event data stored in the EPCIS installed at each site. The inventory at each plant can be monitored automatically from an office instead of having workers at the consolidation center check the inventory every morning and share the inventory information with the managers so that they can plan the daily production schedule of the supplier plant. Consequently, the inventory-checking time of workers at the consolidation center and the inventory errors are reduced, and real-time production planning and inventory control become possible.