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E190 MT.doc E190 MT.doc Document Transcript

  • Xu/1 1.0 Introduction Product tracking is required in three main stages of a supply chain: manufacturing, shipping, and sales. This has been traditionally accomplished by labeling each product with paper identification tags. However, paper is too inefficient to manage on a large scale. In an assembly line that produces hundreds of thousands of products per year, paper tags can easily become misplaced or destroyed. Also, it is impossible to track each item individually in a shipment that contains thousands of items, creating the opportunity for theft. Lastly, paper requires each stage must maintain its own tracking information. For example, while a manufacturer is concerned with serial numbers and product assembly status, a shipper is only interested in the product’s destination. Paper- based tracking systems need to be replaced by a more reliable, efficient, and ubiquitous solution. One alternative is using a radio frequency identification tag (RFID) system instead. By storing data digitally in a microchip, RFID’s can more efficiently and reliably store the same information as a paper ID. A series of sensors reads and validates the information on the RFID’s, and servers maintain a database of information pertaining to each product. The information on the server is online, so its information can be accessed at every stage of the supply chain. This paper will give a technical overview of the RFID system, and then analyze the usefulness of RFID throughout the supply chain. 2.0 Technical Overview An RFID system consists of three components – RFID tags, sensors, and central servers. The flow chart of this relationship is shown in Figure 1. The RFID tag stores a unique identification tag in read-only memory and has a built-in decoder for secure
  • Xu/2 wireless transfer of information. Sensors broadcast a radio signal that can be picked up only by RFID’s within a determined distance. When an RFID tag reads the signal, it will broadcast its stored information back to the sensor. The sensors then route the information through terminals for a server to process. (7:44-46) This entire process operates at 1,200 bytes per second, requiring fractions of a second to complete. (4:90) Figure 1. A flow chart of an RFID system. (Source: Takaragi, K., et al. “An Ultra Small Individual Recognition Security Chip”, IEEE- Micro, Vol. 21, No. 6, Nov/Dec 2001, p. 46) 2.1 RFID Tag An RFID tag is a miniaturized, self-powering, wireless memory module. It stores data that can be accessed by a wireless sensor up to 30’ away. (6:114) It is implemented with a 0.4mm x 0.4mm microchip and connected to a radial antenna. The chip is divided into two circuits: digital and analog. The digital circuit serves as the brain of the RFID, storing, decoding, and encoding data. The analog circuit serves as the brawn, providing power and modulating signals. (7:46-47) Figure 2 shows a sample schematic of an RFID.
  • Xu/3 Figure 2. A sample schematic layout of an RFID chip (Source: Takaragi, K., et al. “An Ultra Small Individual Recognition Security Chip”, IEEE- Micro, Vol. 21, No. 6, Nov/Dec 2001, p. 47) 2.1.1 Digital Circuit By using 0.18µm transistor technology, the digital circuit provides a compact solution for data storage. Data is stored as bits in read-only memory (ROM), with each bit corresponding to one transistor – “on” for 1, “off” for 0. Typically an RFID stores 64-256 bits of data. Because the feature size of the transistors is only 0.18µm, the amount of storable data can be easily customized without significant change to the size of the RFID. The data is written into the ROM when the RFID is manufactured, and cannot be modified afterwards. (7:47) The decoder ensures that the RFID can only be accessed by corresponding sensors. It is composed of a series of complementary metal oxide silicon field effect transistor (CMOSFET) logic gates. When a signal is received by the RFID, the signal is passed through the logic gates to be tested for authenticity. The logic gate network, like ROM, is programmed into the RFID during manufacturing and cannot be modified. (7:46-47) This thwarts all unauthorized used of the RFID. If the signal does not pass the
  • Xu/4 tests, then it was not authentic, and the RFID takes no action. If the signal is determined to be authentic, then the data stored in ROM is encoded by being fed backwards through the logic gates and sent to the analog circuit for transmission. 2.1.2 Analog Circuit The analog circuit takes advantage of the energy storing and filtering capabilities of a capacitor to power the RFID. (7:47) Figure 2 shows a model of the circuit. The antenna, which functions as an inductor, creates current when it picks up a radio signal from a sensor. This current is used to charge the capacitor, which then discharges power into the digital circuit. When data leaves the digital circuit as current, it is passed back through the inductor, which generates a radio signal that is transmitted back to the sensor. Figure 2. A model of the analog circuit in an RFID tag (Source: “Low Cost Electromagnetic Tagging Technology”, Internet: http://web.media.mit.edu/~fletcher/tags/, 1998) 2.2 Sensors Sensors are the simplest component of an RFID system. Their only function is to sense the presence of an RFID, then relay that information. The sensor operates similar to an RFID tag, using CMOSFET logic gates as a signal decoder and encoder. It encodes a signal, then constantly broadcasts it. As stated above, when an RFID that can properly decode the signal comes within the sensor’s vicinity, it will broadcast its information back to the sensor. The sensor then simply decodes the identification information using
  • Xu/5 the same methods as mentioned above, and transfers then sends the information to terminals that route the information to the server. (5:1606) 2.3 Server The true power of an RFID system lies in the servers. RFID tags and sensors only have the ability to store and transmit an identification code. Given this code, the server can perform any task deemed relevant by the user. For example, the server can display the product number, originating factory, manufacturing date and time, name of the employee that assembled the product, destination, and price for each item individually. In addition to just storing information, the server can process the stored information and provide further information for the product. Examples include being able to search for assembly instructions for a product, automatically report to a supervisor whenever a product is moved, and triggering alarms if a product theft occurs. These functionalities can be added or removed to the content of the user without any change to the RFID’s or sensors. (3:90) Another advantage of the server is the ability to perform all its tasks ubiquitously. Because servers can be accessed via the internet, the same server can be used at all stages of the supply chain. This eliminates any miscommunication between the different stages. Shippers can find out exactly where each product has been and where it is going, retailers can lookup assembly process for the product to provide better marketability, and manufacturers can look up sales statistics and make appropriate adjustments to their production. The ubiquitous functionalities available in the servers create practical applications of the RFID system throughout the supply chain. 3.0 Supply-Chain Applications
  • Xu/6 All the amazing technologies in an RFID system would be useless if there were no good applications for it. However in its 5 year existence, groups have been experimenting with RFID’s at all stages of the supply chain. The benefits they have reaped are now serving as examples for other companies that have yet to, or are currently transitioning to RFID. As more groups adopt RFID, more applications for it are being discovered. While all the examples are too numerous to show, some highlights are presented in the following paragraphs. 3.1 Manufacturing Application RFID’s allow the manufacturing process to be much more tightly streamlined than with paper ID’s. Ford Motor Company is an example of a company that has already made the transition to RFID’s. Their facility in Cuautitlan, Mexico operated for years on paper identification sheets. However, due to the hostile environments on the assembly line, many sheets were lost, switched, or ruined, resulting in difficulties in quality control. If welders did not burn a tag, then it was lost in a pile of clutter. With 300,000 to 400,000 cars and trucks being produced each year at this plant, this resulted in increased production oversights, errors, and costs. (4:16) To alleviate their paper-caused headaches, Ford sought out RFID technology to replace paper in their assembly line. They began to program RFID tags with serial numbers and mounted the tags to vehicle frames. As the vehicle moved through the assembly line, sensors could monitor each individual vehicle, and the server reported what had already been completed on the vehicle and what further steps were needed. This drastically cut production time by eliminating the need to manually scan each vehicle, then digging through a filing cabinet to locate information. Vehicles could
  • Xu/7 proceed non-stop through the assembly line, being identified instantaneously when they passed by a sensor. (4:16) RFID technology in the assembly line caught on, and was expanded on by others. A carburetor builder configured its RFID system to not only track their carburetors on the assembly line, but to use the RFID’s to bring up assembly instructions at each stage of the line. Their server detects what model carburetor was being built, and sends instructions for that model directly to the worker. (3:90) This system eliminates any possibility of assembly error due to a human error in identifying the model and the time needed to find the right set of instructions. Because of Ford’s pioneering effort and innovations of other companies, products travel down the assembly line much quicker en route to the shipping ports 3.2 Shipping Application In shipment, there are many opportunities for losses to occur. Typically a single shipment can contain thousands of items. Because of this, it is too impractical to track each item individually, so each case (typically containing 50-100 products) is labeled and tracked. Since individual items are not tracked it is very easy for corrupt employees at a warehouse or trucking company to create one or two “missing” items during shipment. As long as the majority of items in the case remain, the retailer will not know the difference. (2:35) Platex was one of the first companies to try to cease this trend, placing RFID’s on all of their bras. When a case of bras passes by a sensor, each bra will be sensed, notifying the shipper of exactly how many are in the case, where they have been, and where they are headed. (2:35) This gives the shipper the ability to track every item in
  • Xu/8 shipment and be notified if even a single item is lost during shipping. Further, the shipper will know exactly when and where it happened and take appropriate action. In doing so, they have set a standard of getting 100% of what goes out from their warehouses into stores. 3.3 Retail Application Once a product arrives at the retailer and is inventoried, the only way of tracking products is by their individual barcodes. Since it is impractical to scan a barcode everywhere a product moves in the store, many retailers have a hard time locating products in storage. This results in out-of-stock items, slow inventory turnover, and poor customer satisfaction. In the extreme case, a misplaced item in inventory will cause the retailer to purchase another shipment from the manufacturer. The world’s largest retailer, Walmart, is leading the effort for switching to RFID- based inventory systems. According to Linda Dillman, Walmart’s Chief Investment Officer: [RFID] technology will help us know where inventory is all the time. Today, we might know a case is somewhere in the store, but we don’t know if it’s in the back room or on the shelves. … That will help improve our shelf management … We’ll see better tracking and moving of inventory, … improved quality inspection, fewer out-of-stock items resulting in improved shopper satisfaction… (7) That is why Walmart is requiring that by the end of 2005, their entire inventory be equipped with RFID’s. In doing so, they are setting the standard for other companies to follow. Failure to follow will cause companies to be left behind manually organizing and locating items in inventory at the same time that Walmart is selling those same items at a rapid pace. (7) 4.0 Cost
  • Xu/9 All the benefits of RFID can be reaped without a big hit to company budgets. RFID tags cost 2 or 3 cents apiece. Motorola has engineered a system to mount the RFID chip onto a self-adhesive cardboard backing. An antenna is printed onto the cardboard with conductive carbon-based ink, and then the chip is glued into place. (1:24) This technology, combined with the declining cost of microchip fabrication, has driven the price of RFID tags down to a level suitable for mass production. Sensors, while more much more expensive than tags, are not needed in as large of quantities. A Japanese company called Topan Printing Company just introduced a low- power RFID sensor with a retail price of only $17. With a range of 30’, a large 100’x100’x100’ warehouse would only need ten sensors to cover every cubic inch, and then some. (9) Servers are the most expensive component of the RFID system. Sun Microsystems, the world’s leading server producer, sells their premier Sun Fire B1600 Enterprise Server for $24,000. While high in price compared to the other components in the RFID system, servers are a one-time investment. The high bandwidth of the Sun Fire server enables the sensor network to be expanded without a significant loss in processing power. (8) So if a company opens another factory, hires another shipper, or expands its retailer base, the server will be able to seamlessly handle the expansion. Also, since only one server is needed throughout the entire network, the benefits far outweigh the one- time cost. 5.0 Conclusion RFID technology can more than adequately replace paper-based technology in supply chain product tracking. Not only does an RFID system perform the same product
  • Xu/10 identification functions as a paper-based system, but it does so at a much higher speed and reliability level. On top of this, RFID technology allows for the integration of other functionalities into the system. As shown, the benefits of the system far outweigh the costs. A few pioneering companies have set the standard in product tracking by implementing RFID technology. Now all the other companies in the world have the option of following, or being left behind in the dust.
  • Xu/11 References 1. Bak, David. “Paper Transponder Cuts RFID Costs.” Global Design News, Vol. 5, No. 4, Sept 2001, p. 24. 2. Garfinkel, Simson. “An RFID Bill of Rights.” Technology Review, Vol. 105, No. 8, Oct 2002, p. 35. 3. Halliday, Steve. “The Business Case for RFID.” Modern Materials Handling, Vol. 56, No. 2, Feb 2001, p. 90. 4. Johnson, Dick. “RFID Tags Improve Tracking, Quality on Ford Line in Mexico.” Control Engineering, Vol. 49, Issue 11, Nov 2002, p. 16. 5. Karthaus, Udo, Martin Fischer. “Fully Integrated Passive UHF RFID Transponder with 16.7-µW Minimun RF Input Power.” IEEE Journal of Solid/State Circuits, Vol. 38, No. 10, Oct 2003, p. 1602-8. 6. Ruff. Todd M., Drew Hession-Kunz. “Application of Radio-Frequency Identification Systems to Collision Avoidance in Metal/Nonmetal Mines.” IEEE Transaction on Idustry Applications, Vol. 37, No. 1, Jan/Feb 2001, pp. 112-6. 7. Takaragi, Kazuo, et al. “An Ultra Small Individual Recognition Security Chip.” IEEE Micro, Vol. 21, No. 6, Nov/Dec 2001, pp. 43-9. 8. “Sun Fire B1600 Blade Platorm.” Internet: http://www.sun.com/products/blades/, 2004. 9. “Talking RFID with Walmart’s CIO.” Internet: http://www.businessweek.com/technology/content/feb2004/tc2004024_3168_tc16 5.htm, February 4, 2004. 10. “Toppan to Poduce $20 RFID Reader.” Internet: http://www.rfidjournal.com/article/articleview/279/1/1, January 23, 2003