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					         Development of an RFID based Book Retrieval System

     Jung-Wook Choi, Dong-Ik Oh, Sang-Jung Park, Im-Yeong Lee1

Abstract
With quantitative and qualitative growth of libraries, number of books and patrons of the library is
increasing rapidly. However, the growth brings up many new challenges to the library management
process. One of the noticeable challenges is to ease the process of locating books users want. The
purpose of this research is to develop a positioning system that can help library users to locate
books without going through tedious shelf searching process. The R-LIM system we propose can be
used for such purpose. It is based on the RFID technology, and consists of tags, readers, antennas,
wireless terminals and light-emitting diodes. With the system, one may not only locate books easily,
but may also put the book back to appropriate shelves promptly. Since R-LIM can do library
inventories in real-time, it can be used for anti-thief system as well.


1. Introduction

Recent growth of libraries in Korea brought many new challenges to the library management
process. Especially, the management cost is exceeding the limit in many libraries. Core of the
problem is the allocation of labors for book sorting and returns. This problem is especially
noticeable in small libraries such as elementary and junior-high school libraries, where dedicating a
person for such chores is impossible.

Up until now, bar-code based library management system has been prevailing. The system provides
automated management in certain degree, but could not be used for location-based library
management system. One of the most serious problems of today’s library is that the user can not
locate the book he/she wants easily. If the book is misplaced, one needs to search many different
shelves for the book. If the volume of the book is large, this process can take many hours and even
days. Of course, with the bar-code system, we can tell if the book is in the library or not (by
checking the rental/return status of the book), but sometimes we may fail to tell where the book is.
Even if a library has a lot of varieties for patrons, if they cannot locate the items they want, the
fundamental meaning of the library will be lost.

Even when the books are placed in right positions, one usually searches books through a terminal,
write down the location information, moves to an appropriate library section, and search through
several book shelves. It may also take some time as well.

In this research we propose an RFID (Radio Frequency Identification) system that overcomes the
problems mentioned. It helps users search current location of the book in real-time, and in front of
the book case, make users to find the book easily, by just triggering a button on a PDA. The button
triggers a Bluetooth communication and lights an LED attached in front of the book shelf.
1
    Division of Information Technology Engineering, SoonChunHyang University


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2. Technology
2.1 RFID (Radio Frequency Identification)
RFID is an electronic identification technology which recognizes data in a microchip imbedded in a
tag, label, and card through remote antennas. With the technological improvement, it became one of
the most essential technologies in ubiquitous computing [1, 2].

In RFID applications, data attached to a tag is read through wireless communication. The basic
functionality of the application is similar to that of the bar-code system, but not like bar-code labels,
RFID tags can be read remotely without putting the reading device close to the tag. Also, not like
the bar-code scanning, multiple tags can be read simultaneously.

Microchips used for RFID tags can be as small as to be placed in a paper sheet. It will be ready for
wide range of applications, since the price will go down to 5-7 cents per tag in a near future [3].
Typical FRID system consists of tags, readers, and antennas. A tag stores data in a microchip it
holds. Readers are used to read data from the tag. It can also be used to write data to the tag.
Antennas are used for wireless communication using appropriate protocols and data communication
channels.

The technology is under development throughout the world. Domestically, it is used for payment
cards for public transportation (buses and subways). It uses 13.56MHz wireless frequency band. In
many countries, systems are under development for different areas, such as retail store management.
Besides the 13.56MHz band, 900MHz, 2.4GHz, and 5.8GHz bands are considered for the RFID
communication.

Different frequency bands carry different characteristics. One should examine their characteristics
when building an RFID application. In general, as the band goes higher, the longer the reading
distance it can handle. However, the cost increases as the band goes up [5, 6]. Table 1 summarizes
characteristics of different radio bands used for RFID [7, 8].
                                 Table 1. Various Frequency bands for RFID
  Frequency band                                          Characteristics
                       Distance: Under 45cm
      135 KHz          Price: Low
                       Description: Very first band used. No anti-collision mechanism. Used mainly for
                       gate-keeping, animal tagging, and automobile locks.
                       Distance: Under 1m
    13.56 MHz          Price: Moderate
                       Description: Standard in Korea. Same band with smart cards. For read and write. Up
                       to 20 simultaneous tag reading.
                       Distance: 3 5m
   860~960 MHz         Price: high
                       Description: Under discussion for standard. Longer read range. Shorter antenna.
                       Distance: 1~1.5m
   2.45~5.8 GHz        Price: high
                       Description: Standard for toll collection. Similar to UHF band. Smaller tag size.




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2.2 Bluetooth
Bluetooth is a technology covering protocols and products that can be used for bi-directional
wireless communication between various hardware devices. This technology was started by
Ericsson in 1994 for low battery powered, low priced solution for wireless communication between
terminals and peripherals, such as PDAs, notebooks, mobile phones, and peripherals [9, 10].

The major advantage of Bluetooth lies in its built-in security features (Keys, Authentication,
Encryption, etc), which made it ready for Electronic Commerce.

Bluetooth spectrum covers frequency bands between 2.402GHz to 2.480GHz in every 1MHz
interval. The maximum frequency hopping rate is 1600hops/s and wireless link can be 10· to 10m.
With the increment of power, it may cover up to 100m [10, 11].

It became one of most popular mechanism for short distance wireless communication especially in
home and office environment. It can be easily integrated with any type of wired/wireless network.
Its typical area of application is in notebook phones, Internet Bridge, data synchronization, mobile
peripherals, and wireless headsets [10].

3. R-LIM system

In this project we developed a book locating system called R-LIM (RFID based Library Information
Management) system in order to solve various problem mentioned in Section 2. It is based on RFID
technology and Bluetooth communication. Figure 1 depicts overall structure of the system.

                          RFID Reader



                          RFID Antenna




                           LED(7-segment)




                                         PDAs for book retrieval          Server

                                   Fig 1. Structure of the R-LIM System




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In this system, an RFID tag is attached to each library book. The tag holds identification number of
the book, and information associated with the book is maintained in central database. Books are
placed on shelves as usual. The shelf has antennas placed on top of it. And each antenna is
associated with an LED in front, as it is shown in Figure 1. Tag number associated with the book is
read through the antenna automatically, along with the ID number of the antenna it is being read.
The information is sent to the central database, so that current location of the book can be traced in
real-time. Information in the central database is synchronized with user mobile devices (PDAs).
Users may search items of interest using a PDA and moves to the place, following the location
information provided. In front of book stands, user triggers the lighting button, and an LED near the
book will be turned on.

The overall structure of the system seems adequate. However, there are some details we need to
consider. First, there might be a possibility that multiple users search books side by side. In this case
lighting an LED is not enough because when more than one LED is lighted, we do not know which
one belongs to which person. Therefore, instead of using simple LEDs, we use 7-segment LEDs to
display ID number of PDA on the LED. Second, we may need to install multiple antennas on a shelf,
because of the granularity of the location information. If there are many books on the shelf, the
more the antennas, the shorter the searching time will be. If the cost of antenna is too high we may
let one antenna to cover multiple shelves. Antennas should be placed where cross section of
covering area becomes minimal. If multiple antennas pick up the same tag information, we use only
one. This is no problem because the user knows the book is some where very close to the lighted
LED.

RFID reader is another main component of the system. It collects tag information from antenna and
sends it to the central database. Its main function is to read multiple tags simultaneously using
collision detection algorithm. Another important role is to identify antenna from which the tag is
read. For R-LIM, a reader can connect up to 4 antennas and perform such functionalities. For
lighting LED, we placed Bluetooth units to PADs (sender) and LED controllers (receiver). We
programmed both units so that when user triggers the button, a correct LED is turned on. Figure 2
shows the logic of Bluetooth and LED lighting portion of the system.
                                              7-Segment




                                                                             PDA
                           PCB for lighting
                                                                                 A
                                                                           ID_
                                                                     er,
                                                               r
                                                          ·

                                                                   · BT Module Initialization

                              Bluetooth Module




                                                              · ID_reader, Addr_bluetooth module, ID_PDA




                                Fig 2. LED Lighting and Bluetooth communication




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When users take books off the shelf, the system should be able to reflect such information in real-
time fashion. This can be achieved by configuring time interval of the reader so that it sends
updating information to the central database only when it is needed. However, if the user is carrying
a PDA, it can not be synchronized with the database. The location information of the book may not
be proper then. Therefore, a mechanism to reflect such real-time information is necessary. This can
be achieved, if PDAs can be synchronized remotely. Our research group is currently working on
this feature, utilizing local area network access mechanism. Once this feature is implemented, we
can easily perform real-time inventory of the library, so that we may use the system for anti-thief
functionality as well. With such finer grained information, we may also provide user a better
information, such as in what cart or table the book is currently on.

4. Conclusion

In this paper, we proposed a book locating system which can solve many problems of fast-growing
domestic libraries. With growing book volume and number of patrons, today’s library users spend
longer time for locating books. Librarians also spend more and more time placing books to
appropriate places. R-LIM can solve such problems, utilizing RFID technology and Bluetooth
communication.

In R-LIM, we attach an RFID tag to each book, place antennas to book shelves, and connect them
to RFID readers. The reader reads the tag information and sends it to the central database. Along
with the tag information, the ID of antenna which read the tag is also sent. Therefore location of a
book can be associated with an antenna. Using this information, users can locate book by lighting
the LED paired with the shelf (antenna). This will dramatically save time for both patrons and
library management staffs, so that enhance the satisfaction level of patrons while saving laboring
cost.

Reference

[1]    RFID Journal, http://www.rfidjournal.com/
[2]    Klaus Finkenzeller, RFID Handbook : Fundamentals and Applications in Contactless Smart Cards and
       Identification, John Wiley & Sons, 2003

[3]    Association for Automatic Identification and Mobility, http://www.aimglobal.org/
[4]    http://www.rfidusa.com/
[5]    Susy d'Hont, The Cutting Edge of RFID Technology and Application for Manufacturing and Distribution, Texas
       Instrument TIRIS

[6]    Klaus Finkenzeller, Rachel Waddington, RFID Handbook : Radio-Frequency Identification Fundamentals and
       Applications, John Wiley & Sons, 2000

[7]    http://www.uwebc.org/
[8]    http://www.ecn.purdue.edu/
[9]    http://www.bluetooth.or.kr/

[10]   Jennifer Bray & Charles F. Sturman, BLUETOOTH connects without cables, PRENTICE HALL PTR
[11]   http://www.mmctech.com/




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