functional model may better guide design and development of the. RFID applications by its use as an instrument for definition of requirements. Keywords: RFID ...
SEMANTIC BREAKDOWN OF RFID FUNCTIONALITY TO SUPPORT APPLICATION DEVELOPMENT
VIC MATTA Ohio University Athens, OH 45701
DAVID KOONCE Ohio University Athens, OH 45701
Abstract
critical mass of adoption as the crossing of a chasm after which adoption was imminent [15]. Wide deployment of RFID technology began in 2000 after standards for its communication technology were established [10]. Since then, applications of RFID technology have been found in closed-loop as well as open-system applications. In closed-loop applications, RFID systems are not dependent on the state of technology of external partners. In open system applications, RFID systems must take into account prevalent standards and the state of adoption of RFID systems, since their value is greatly enhanced by network effects in which a supplier or a shipper’s use of the RFID system increases the value of the RFID technology [11]. As a current example of a closed-loop application, Nike released a product called “Nike+ Sportkit”, that uses a proprietary in-shoe RFID tag to interface with an iPod to provide pedometerlike data for distance traveled on foot [19]. Such applications of RFID technology, while highly functional, use RFID in a closed loop in which the tags do not interface with a device other than a single iPod receiver. On the other hand, open system applications of RFID technology exist in the supply chain sector. Member organizations of the supply chain range from suppliers of raw materials, to manufacturers, to wholesalers and distributors, to retailers [21]. Their use of RFID in tracking the movement of products from production to the retail point of sale in real time provides higher visibility of assets, and facilitates better management of inventory and logistics [27]. RFID’s promise of logistical efficiencies in tracking goods in the supply chain has caused Wal-Mart and the Department of Defense to mandate their top suppliers apply RFID tags on pallets [24]. While this application has followed well established standards, not all suppliers have been able to benefit from their RFID implementations. Most suppliers to Wal-Mart and Department of Defense were pressured into adoption, and did not have other venues for application of RFID technology to justify a strong return on investment [24]. There were only a few organizations that found additional uses of the technology, such as one manufacturer who put the RFID technology to use in the manufacturing processes for process control and logistics visibility on the shop floor in addition to packaging and shipping [22]. RFID equipment is expensive, and implementations of RFID systems require a software overhaul [23] sometimes making it a cost prohibitive venture. To achieve adequate return on investment, implementations of RFID technology in a firm must execute a systematic analysis of requirements towards the proposed applications. Once all requirements are established, they must be mapped across the functionalities provided by RFID technology as shown in this research. Few studies present a comprehensive analysis of the functionality of commercial applications of technology [26], The purpose of this research therefore, is
In this concept paper, we study the complex innovation of Radio Frequency Identification Systems (RFID) in context of their functional value. The purpose of this research is to provide an interpretation of functionality as presented by contemporary RFID systems and organized in the form of a functional matrix that demonstrates RFID mainstream applications. The fundamental functions are broken down into three core areas of Identification, Location and State. Identification is shown to be paramount — especially because of the serial number uniqueness carried by contemporary ‘Gen2’ RFID tags. Location is an inherent function with several sub-classifications depending on whether it is based on proximity or proxy. Finally, the function of state (such as temperature) is shown to be a specialized application of RFID. Applications that use these functions are discussed and plotted in the form of a simple matrix. The expectation is that the functional model may better guide design and development of the RFID applications by its use as an instrument for definition of requirements. Keywords: RFID, semantic model, model of functionality, automatic identification, function, functional matrix, RFID applications, planning, requirements definition. Introduction Radio Frequency Identification (RFID) systems use electromagnetic fields to automatically identify objects. These systems consist of readers, tags and an underlying framework for further processing of data. RFID tags carry data that is queried by readers which hold, lookup, store or otherwise process this information. Tags vary in frequency, size, data capacity, range and, response speed. RFID readers, also called scanners, are matched with the tags with which they are meant to work. An RFID System is typically built around the desired application and uses a framework to process, store and transmit the acquired information. Background The adoption of RFID technology and its rate has been discussed in numerous articles. The hype about this technology has been around [14], but standards and reliable solutions are still being worked out [7; 9]. Very often the impact of an increasing number of peers who are using RFID technology creates a need to stay current with prevalent technology trends in business and industry. This is termed the network effect, and often determines the success or failure of a technology [11; 25]. For example, in the case of barcodes, success of its adoption depended on whether a critical mass of adopters had been reached, at which point, mass adoption of the innovation drove itself [20]. Moore spoke of
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to conduct a careful and complete semantic analysis of the functionalities provided by RFID technology, and demonstrate a mapping of those functionalities to contemporary applications.
Figure 1: Functional Domains
Characteristics of the Technology Before considering the core functionalities provided by RFID systems, it is important to address how they are different from operational characteristics. When functions are related to business application of RFID systems, operational characteristics are physical properties that improve with advances of technology, such as: speed, range, strength of transmission, increased memory and read ranges, the ability to read/write data on the tag. These characteristics are inherently tied with the existing state of technology. Since new technologies advance quickly, characteristics improve. Over the past few years, characteristics such as speed, reliability, range and security have all seen continuous improvements in their abilities to provide solutions. For example, one of the early technological challenges of RFID was in read reliability through liquids and metals, because radio waves bounce off of metals and are absorbed by liquids at ultra high frequencies. This issue caused misreads while receiving shipments of cans of soup [23], for example. With advances made in RFID technology, readability through liquids and metals has been improved by standardizing the use of High Frequency instead of Ultra High Frequency RFID tags for such applications [12]. The operational characteristics are seen as simply properties of RFID tags and systems developed to realize operational benefits. The purpose of listing such characteristics is to clarify and differentiate them from core semantic functionalities that are addressed here. In the next section, we discuss functional domains of the RFID technology in detail. This is followed by a discussion showing the combination of functionalities used by various applications. Finally, we end with a case for using the functional matrix in defining requirements before applications are developed and deployed. Functional Domains of RFID Systems In this section, we will discuss, in detail, three high level functions that RFID systems intrinsically provide to the business community. To classify the functions provided by an RFID tag and system from a conceptual perspective we consider the RFID tag and system removed from any specific application and attempt to describe the fundamental functionality presented by this technology. We identify these core functions as: Identification, Location, and State. Identification is a property by which a tagged object can be uniquely identified. Location is the representation of positions based on proximity and the privilege to proxy. Finally, state refers to environmental conditions in which a tag may be present. Figure 1 shows how these functions of location and state depend upon identification as their base. All applications that use RFID need the function of identification in some form. Other functions such as location are only relevant when the item is identified. Location and state are second layer functionalities and can be a significant part of the RFID tagged items.
in designated server systems known as Object Name Servers (ONS) to make sense of the RFID serial number. These servers operate in much the same manner as a domain name server (or DNS) which transform web addresses into IP addresses and vice versa. As depicted in Figure 1, other functionalities of RFID are built on the foundational nature of the tag’s identification function, and are relevant only when identification can be presumed. The serial number in each tag is unique without reference to the system that reads it. It is interesting to compare the characteristics of identification between RFID and barcode IDs. With RFID, each tag is independently unique. In other words, the serial number carried in the memory of an RFID tag would be unique without adding on (meta) data like time, date, place, origin, or manufacturer/product identifier numbers [1]. In comparison, barcodes on items (a pack of Gillette blades, for example) are identical and can only be made unique when used in reference to a system which applies such meta data. Therefore it can be said that barcodes provide class level identification. For example, a six pack of Mach IV Gillette shaving blades would have the same barcode as any other six pack. This is not the case with RFID in which every single six pack of Mach IV Gillette shaving blades would have a unique serial number carried by the RFID tag. RFID tags can be said to possess instance (of a class) level identification. 2. Location: One of the key functionalities presented by RFID technology is its ability to provide location. An RFID tag may move over large physical distances, and be scanned using multiple readers while in transit. Members of the supply chain are interested in knowing where a shipment is at all times. The geographical position of the tag is important as it travels through the supply chain. This locational functionality can be classified into two categories: one in which the proximity of an individual tag to a scanning system is significant, and the other in which the capacity of one tag to represent a group of others is significant. We denote these two classifying characteristics as proximity and proxy as shown in Figure 2 below. 2a. Location by Proximity: We use the function of location by proximity when the tag is in the neighborhood of the reader. For example, electronic article surveillance (EAS) systems are used for theft detection at entry/exit points in supermarkets. Theft is prevented when the scanners at the exit points detect an RFID tag that is not “killed” by the checkout systems as a part of the purchase process. Scanners only detect the tag when the tag comes closer than a pre-fixed threshold distance.
1. Identification: The role of identification in RFID is cardinal. It forms the basis of its application in the industry. RFID tag data uses databases
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Figure 2: The Location function
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In this way, the locational function of proximity is used for theft prevention. 2.a.1. System Containment: When the proximity function is used in the context of containment within an RFID enabled system, it is considered to be a special case of proximity. In typical scenarios, this is used to aid in making decisions of logistical efficiency in transportation or even locating a tool within in a tool crib. A package may pass through several scanners in transit to its final destination and providing a traceable path and a sense of location within the shippers system. For example, Fedex tracks packages when they arrive and depart their warehouses while in transit to the recipient. This information is then made available to their customers to provide in-transit visibility (a term popularized by the Department of Defense) [3]. 2.b. Location by Proxy: This type of functionality is used when a tag has the implicit privilege of representation of other tags within a specified boundary. The purpose of representation is for practical purposes, and the representing tag is considered a higher level tag. When such a higher level tag stands for other tags, it may do so for one of two reasons: containment or composition. 2.b.1. Location by Proxy for Containment: A single tag may represent containment of several other tags. The association of the higher level tag in representing its contents is temporal, since contents of a container are typically easy to swap in and out, and RFID tags are capable of being updated fairly easily. For example, an RFID tag on a pallet or a shipping container may be coded to symbolize the collection of cases of items that are contained within the pallet at that moment in time. Therefore, when the pallet changes state, like its location, only one tag needs to be updated. 2.b.2. Location by Proxy for Composition: Here, a single tag is used to persistently (in contrast with the temporary function of location by proxy for containment) represent other tagged items located in its neighborhood that it is composed of. In case of proxy for composition, the tags (or tagged items) that comprise the higher level tag (or tagged item) have little or no significance once assembly of the composite object is complete. This state of the higher level tag being a proxy for its compositional tags is typically permanent. The completed item is not expected to change with the frequency that is seen in the tags that proxy for containment, and therefore differentiates itself from that subcategory. For example, an automobile may be made up of several RFID tagged items. Once the automobile has been assembled, a single tag is used to represent the automobile and not the all the tags that were used to make it. The location of this higher level tag is much more practical to update about than the location of the tags that make up the automobile. 3. State: The function of state is depicted by the ability of a tag to sense conditions in its neighborhood, and represent and record that state as data. This ability of the tag is further classified into tags that record data from crude physical sensors, or sophisticated mechanisms. In either case, state is about sensing and recording environmental conditions which include, but are not limited to temperature, pressure, presence of water (or humidity), light, dirt, pH level, motion, and so on. This list of “capabilities” may continue to expand technology progresses. 3.a. Crude tags: RFID tags that use simple, crude, physical, non-electronic and natural sensing mechanisms/devices are classified as crude. Crude RFID tags are typically more reliable
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Figure 3: The State function since they are solid state tags. However these types of tags inherently suffer from limited functionality such as the inability to quantify the state to some extent, due to the natural and/or physical types of mechanism used. Such tags typically provide a dichotomous representation of state changes. A second inherent characteristic is that they are typically good for single uses or single response only, since not all physical changes are easily reversed. For example, chemical transformation of magnesium in an RFID tag could be used for sensing water/humidity; or the magnetic deactivation of tags at checkout counters in EAS systems [1]. 3.b. Sophisticated tags: These are RFID tags that use sophisticated, often electronic sensors read and record the state of the environment. These tags often have the ability to record this information over time. For example, a tag may be used to ensure that the temperature inside a shipment of ice-cream does not climb above 32ºF for any extended period of time. Use of battery power is made to sense and store environmental data. Often these battery powered tags also use this energy to transmit their identity wirelessly. Known as Active RFID tags, some of these tags are capable of many other higher level functions, especially in conjunction with Wireless and GPS technology to sense and transmit their location. Discussion As seen in the previous section, the three functional domains of Identification, Location and State have distinct characteristics. The applications listed below are plotted in Table 1. The items numbers seen below correspond to the numbers used in the table. The purpose of the table is to demonstrate how applications use a combination of several functional domains discussed. 1. Real time tracking and quality assurance of Audi TT Sports car’s chassis during its production cycle on the shop floor. The tags store information to uniquely identify the chassis during production, painting and curing of chassis [2; 6], and to tag the chassis on completion, a function of Composition-based Location by Proxy. 2. Fedex has integrated their warehouse and transportation management systems using RFID for effective tracking of assets [13]. These systems track packages in transit or in storage providing location-based functionality. In this case, System Containment is implicit because the asset being tracked could be expected to reside within the Fedex system until delivery. 3. In September 2004, Wal-Mart announced a pilot project mandating that by January 2005, their top hundred suppliers to conform to palette level tagging using EPC compliant RFID tags[18]. The RFID tags on pallets represent its contents and thus exhibit Containmentbased Location by Proxy. 4. RFID based systems can be used to manage and track
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tools in a tool crib, as well as grant access to it. This allows for faster and more accurate toolroom inventory management [5]. Granting of access is a function of Identification only, while tracking of tools and their usage within a system is a function of Location, and more specifically Proximity-based System Containment. 5. TempSens uses RFID technology to monitor temperature data and transmit it wirelessly to a scanner. This is being used in meat, grocery and pharmaceutical industries for ensuring that the temperature of goods in transit did not exceed a preset threshold value [17]. The TempSens RFID tag combines the ability to log temperature data with active RFID tags that use thin film batteries, exhibiting the sophisticated function of recording and transmission of State. 6. EAS systems use a single bit RFID tag that is electromagnetically killed at a checkout counter. The process used to kill the tag is simply the application of a magnetic field that changes the state of the RFID tag,
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an example of Crude change of State [1]. It should be noted that EAS tags are unsophisticated and with the single bit, cannot provide unique identification. They do, however, identify the unpurchased item as being a tracked item, often of high value. 7. The Baja Beach Club, a prestigious night club in Barcelona, Spain, uses a subcutaneous RFID chip called Verichip, developed to identify its members who would not have to wait in line for admission [8]. The application of this RFID chip is simply an example of Identification only, since no form of Location or State are involved. Conclusion Since their first commercial use for detection of friendly aircraft in World War II, RFID technology has been developed for use in an eclectic range of applications. These applications have often evolved without a thorough investigation of its functionalities and potential applications – something that is done in the requirements
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definition phase of a Systems Development Life Cycle (SDLC). This is one of the cornerstones of success of a project, and is concerned with specifying goals for, functions and constraints of a project [16]In most endeavors, this phase directs the design of the application, which in turn defines its development. For instance, IS development begins by developing an understanding of the application domain [4]. The purpose of breaking down the functionality provided by RFID tags and systems is to use it to design application before they are developed. We expect to use this classification of functionality of RFID technology to serve as a guide in assessing the requirements of application before deploying well thought out, mature solutions that often provide competitive advantages [26]The core functions of RFID systems discussed have been tabulated in Table 1, a few applications which serve as examples are discussed in detail. These functions can be summarized by Figure 4. A few fundamental points can be stated about the functions: 1. The role of identification has increased in importance, especially due to its ability to uniquely identify tagged objects. This is further corroborated by the presence of ‘X’ across all the applications, in Table 1. 2. Location is the second most significant and broadest function having several sub-classifications. The trans ponder that scans a tag implicitly conveys the location of the tag by way of its own location. No supply chain application of RFID is complete without the function of location being inherent in its implementation. 3. State is a third and a largely exclusive function carried by active or even semi-passive RFID tags (that use batteries to store but not to transmit data). By far the most common application of the state functionality is that of theft prevention by EAS systems. As an example of a well-planned implementation, EZPass was the first multiple use of an RFID system across different business segments. And while the functionality — identification, was the same for each data collection operation, the identification spanned organizations as varied as toll booths, parking lots and gated communities [10]. Awareness of functionalities of RFID across potential applications before its implementation will hopefully provide well thought out, cost justified implementations. References [1] Asif, Z., & Mandviwalla, M. (2005). Integrating the supply chain with RFID: A technical and business analysis.
Communications of the AIS, 2005(15), 393-426. [2] Bachelor, B. (2007). Audi uses semi-passive tags to make TTS. Retrieved April 6, 2008, from http://www.rfidjournal. com/article/articleprint/3002/-1/1/. [3] Estevez, A. (2005). RFID vision in the Dod supply chain. Acquisition Process Improvement Retrieved April 6, 2008, from http://www.dau.mil/pubs/dam/05_06_2005/est_mj05. pdf. [4] Evermann, J., & Wand, Y. (2006). Ontological modeling rules for UML: An empirical assessment. Journal of Computer Information Systems, 47, 14-29. [5] Felix, C. Inventory control systems for the shop. Retrieved April 6, 2008, from http://www.productionmachining.com/ articles/100602.html [6] Gain, B. (2007). Tracking audis with rfid. Retrieved April 6, 2008, from http://blog.wired.com/cars/2007/01/tracking_ audis_.html. [7] Halliday, S. (2005). A standards update - An introduction to RFID standards. Newsletter, Retrieved April 6, 2008, from http://www.hightechaid.com/stdsupdate/stds_update1.htm [8] Jacobsen, A. (2004). Chip the vip. Retrieved April 6, 2008, from http://www.rfidbuzz.com/news/2004/chip_the_vip. html. [9] Jeyaraj, A., Rottman, J. W., & Lacity, M. C. (2006). A review of the predictors, linkages, and biases in it innovation adoption research. Journal of Information Technology, 21(1), 1-23. [10] Landt, J. (2001). Shrouds of time: The history of RFID. Retrieved April 6, 2008, Retrieved from http://www. rfidconsultation.eu/docs/ficheiros/shrouds_of_time.pdf. [11] Liebowitz, S. J., & Margolis, S. E. (1998). Network externalities (effects). Retrieved April 6, 2008, from http:// wwwpub.utdallas.edu/~liebowit/palgrave/network.html. [12] Lundstrom, S. (2004). The bottom line: RFID will have a dramatic impact on the operation of global supply chains over the next 10 years. AMR Research. [13] Mason, S. J., Mauricio Ribera, P., Farris, J. A., & Kirk, R. G. (2003). Integrating the warehousing and transportation functions of the supply chain. Transportation Research: Part E, 39(2), 141. [14] Matta, V., & Moberg, C. (2006). The development of research agenda for rfid adoption and effectiveness in supply chains. Issues in Information Systems, 7(2), 246-251. [15] Moore, G. A. (2002). Crossing the chasm Collins. [16] Navarro, E., Letelier, P., Mocholi, J. A., & Ramos, I. (2006). A metamodeling approach for requirements specification. Journal of Computer Information Systems, 47, 67-77. [17] New low-cost temperature sensor. (2002). Retrieved
Figure 4: Complete RFID Functionality Diagram
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April 6, 2008, from http://www.rfidjournal.com/article/ articleprint/28/-1/1/. [18] Palamides, T. (2004). Rfid forum. Retrieved April 1, 2008, Retrieved April 6, 2008 from http://www.wireless.ucla.edu/ techreports2/RFID-2004-Forum.pdf. [19] Saponas, T. S., Lester, J., Hartung, C., & Kohno, T. (2006). Devices that tell on you: The Nike+iPod sport kit. Retrieved April 6, 2008, from http://www.cs.washington.edu/research/ systems/nikeipod/tracker-paper.pdf. [20] Seideman, T. (1993). Bar codes sweep the world. Invention and Technology Magazine Retrieved April 6, 2008 from http://www.americanheritage.com/articles/magazine/ it/1993/4/1993_4_56.shtml. [21] Siau, K., & Tian, Y. (2004). Supply chains integration: Architecture and enabling technologies. Journal of Computer Information Systems, 44(3), 67-72.
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[22] Sparkes, M. (2006). Gambling on chips. Manufacturing Engineer, 85(4), 10-11. [23] Spekman, R. E., & Sweeney, P. J. (2006). Rfid: From concept to implementation. International Journal of Physical Distribution and Logistics Management, 36(10), 736-754. [24] Sullivan, L. (2004). Walmart’s way. InformationWeek, 3650. [25] Sundararajan, A. (2003). Network effect. Retrieved April 6, 2008, from http://oz.stern.nyu.edu/io/network.html. [26] Yeung, W. L., & Lu, M.-T. (2004). Gaining competitive advantages through a functionality grid for website evaluation. Journal of Computer Information Systems, 44(4), 67-77. [27] Zhang, C., & Li, S. (2006). Secure information sharing in internet-based supply chain management systems. Journal of Computer Information Systems, 46(4), 18-24.
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