Tham khảo tài liệu 'sustainable rfid solutions part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 64 Sustainable Radio Frequency Identification Solutions RFID offers the possibility to measure precise residence time in the process. The RFID tags would be used as the start and the end points of each batch. And process data can then be linked to a virtual production batch Kvarnstrom Oghazi 2008 . From the test results in the iron ore distribution chain in order to achieve a sufficient read rate more than 50 it is necessary to use RFID tags that are larger that the pellets Kvarnstrom Oghazi 2008 . However they proved that their technique may be used to create traceability in the continuous process chain. 4. Challenges There are several challenges in deploying RFID for traceability. One of the main challenges comes from the inherent technical nature of RFID. RFID tags may collide with each other when multiple tags try to respond to the reader simultaneously. Thus there is no guarantee that a tag will be continuously detected on consecutive scans Floerkemeier Lampe 2005 . Given the fact that it does not provide 100 read rate most of the data models and tracing mechanisms to provide an efficient way for traceability would almost be useless. However lots of efforts poured by engineers have increased the level to almost 99 and in the near future the technology will be matured to the level of the existing barcode system which has no problem of reading items. RFID tags are subject to price and size constraints. Although the tag price is continuously decreasing companies are hesitant to use RFID because of the price disadvantage over barcode. Since tags derive energy from readers in the case of passive tags their communication bandwidth is limited Zarolostas et al. 2007 . In addition due to their small size requirements tags have limited memory which indicates that the stored information on tags is also limited Sarma et al. 2001 . Another important facet of RFID-enabled traceability is that the amount of information generated by the infrastructures as items pass through .
