Abstract:
An advertisement management device generates and manages advertisement information and an advertisement identifier, a tag management unit generates a tag identifier and tag information unique to the tag identifier, and manages the tag identifier, the tag information, and the advertisement identifier generated by the advertisement management device in associated manner. The tag management unit sends the tag identifier and the advertisement identifier to the radio tag. A reader reads the tag identifier and the advertisement identifier from the radio tag, sends the tag identifier to the tag management unit, and sends the advertisement identifier to the advertisement management unit. The tag management unit sends tag information corresponding to the tag identifier received from the reading unit to a display unit, and the advertisement management unit sends advertisement information corresponding to the advertisement identifier received from the reading unit to the display unit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to management of a radio tag, and specifically relates to display of information on a terminal about an item to which a radio tag has been attached. 
     2. Description of the Related Art 
     Radio tags have already been widely used. To promote the radio tags further, it is necessary to reduce the cost of the radio tags. One approach to reduce the cost of the radio tags, apart from reducing the production costs or the costs for attaching the radio tags to items, is to produce revenue from the radio tags. One approach to produce such revenue is to display on a terminal an advertisement of the item, to which a radio tag is attached, when a customer is interested in that item. 
     For example, advertisements and tag IDs can be managed in a database, and when a customer tries to check the traceability information of a radio tag, an advertisement associated with a tag ID of that radio tag can be displayed on a terminal for the purchaser to see. 
     Japanese Patent Application Laid-Open No. 2003-224677 discloses a technology in which a radio tag communicates with a mobile telephone and causes the mobile telephone to display an advertisement. 
     In the conventional technology, however, private information can leak. Why and how the private information can leak is explained below with reference to  FIG. 16 . 
     As shown in  FIG. 16 , a radio-tag management device  20  manages tag information and tag IDs in associated manner for a plurality of radio tags. Each of the radio tag stores therein tag information relevant to itself along with its own tag ID. 
     For example, when the radio tag is in a production stage, only tag information A that is required in the production stage is stored in the radio tag. When the radio tag is in a distribution stage, only tag information B that is required in the distribution stage is stored in the radio tag. The radio-tag management device  20  manages all the tag information, such as tag information A, tag information B, tag information C, for all the radio tags for all the stages. As the stages change, tag information corresponding to the new stage is overwritten on the tag information of the previous stage in the radio tag. The tag information stored in a radio tag includes traceability information relating to an item to which the radio tag is attached. The traceability information includes information relating to producer and/or seller of the item. 
     An advertisement management device  10  manages tag IDs and advertisements in an associated manner for all the radio tags. Assume that a customer becomes interested in an item and tries to check traceability information, which is stored in a radio tag attached to the item, of the item by using a user&#39;s terminal  30 . In this case, a tag ID of the radio tag attached to the item is sent to the advertisement management device  10  and the advertisement associated with the tag ID is fetched from the advertisement management device  10 , and the advertisement is displayed on the user&#39;s terminal  30  together with the traceability information. 
     However, because the tag IDs are managed on the advertisement management device  10 , a person who has access to the advertisement management device  10  can readily and fraudulently acquire traceability information of all the radio tags. Thus, the traceability information, which is private information, can readily leak to a third party. 
     Thus, there is a need of a technology that can prevent leakage of personal information in a radio tag system. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     According to an aspect of the present invention, a computer-readable recording medium stores a computer program causes a computer to manage information on a radio tag, the computer program causes the computer to execute requesting issue of an advertisement identifier for identifying an advertisement, to an advertisement management device which manages the advertisement to be displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; receiving the advertisement identifier requested in the advertisement-identifier-issue requesting step from the advertisement management device, and storing the advertisement identifier associated with a tag identifier in a storage device; and writing the advertisement identifier stored in the storage device in the advertisement-identifier storing step, to the radio tag to which the corresponding tag identifier has been written so that the advertisement identifier can be read from the radio tag and specified when the user&#39;s terminal requests the advertisement to the advertisement management device. 
     According to another aspect of the present invention, a radio-tag management method for managing information on a radio tag includes requesting issue of an advertisement identifier for identifying an advertisement, to an advertisement management device which manages the advertisement to be displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; receiving the advertisement identifier requested in the advertisement-identifier-issue requesting step from the advertisement management device, and storing the advertisement identifier associated with a tag identifier in a storage device; and writing the advertisement identifier stored in the storage device in the advertisement-identifier storing step, to the radio tag to which the corresponding tag identifier has been written so that the advertisement identifier can be read from the radio tag and specified when the user&#39;s terminal requests the advertisement to the advertisement management device. 
     According to still another aspect of the present invention, a radio-tag management device that manages information on a radio tag includes an advertisement-identifier-issue requesting unit that requests issue of an advertisement identifier for identifying an advertisement, to an advertisement management device which manages the advertisement to be displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; an advertisement-identifier storage unit that receives the advertisement identifier requested by the advertisement-identifier-issue requesting unit from the advertisement management device, and stores the advertisement identifier associated with a tag identifier in a storage device; and an advertisement-identifier writing unit that writes the advertisement identifier stored in the storage device by the advertisement-identifier storage unit, to the radio tag to which the corresponding tag identifier has been written so that the advertisement identifier can be read from the radio tag and specified when the user&#39;s terminal requests the advertisement to the advertisement management device. 
     According to still another aspect of the present invention, a computer-readable recording medium that stores a computer program causes a computer to manage advertisement, the computer program causes the computer to execute issuing an advertisement identifier for identifying an advertisement in response to a request from a radio-tag management device which manages information on a radio tag, the advertisement being displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; and transmitting an advertisement in response to a transmission request of the advertisement corresponding to the advertisement identifier sent from the user&#39;s terminal which reads the advertisement identifier from the radio tag when the tag information for the radio tag is displayed, the radio tag to which the advertisement identifier issued in the advertisement-identifier issuing step has been written by the radio-tag management device. 
     According to still another aspect of the present invention, a computer-readable recording medium that stores a computer program manages a user&#39;s terminal, the computer program causes the computer to execute reading an advertisement identifier for identifying an advertisement related to an item attached with a radio tag, from the radio tag; requesting transmission of an advertisement to an advertisement management device which manages the advertisement associated with the advertisement identifier corresponding to read advertisement identifier; and displaying an advertisement received from the advertisement management device along with tag information. 
     According to still another aspect of the present invention, a method of using a radio tag includes an advertisement management device issuing an advertisement identifier for identifying an advertisement, the advertisement management device managing the advertisement displayed together with tag information by a user&#39;s terminal used by a purchaser of an item attached with a radio tag; a radio-tag management device, which manages information on a radio tag, writing the advertisement identifier issued at the advertisement-identifier issuing step, to the radio tag; and the user&#39;s terminal reading the advertisement identifier written to the radio tag at the writing, receiving the advertisement corresponding to the advertisement identifier from the advertisement management device, and displaying the advertisement together with the tag information. 
     According to still another aspect of the present invention, a method of managing advertisement includes issuing an advertisement identifier for identifying an advertisement in response to a request from a radio-tag management device which manages information on a radio tag, the advertisement being displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; and transmitting an advertisement in response to a transmission request of the advertisement corresponding to the advertisement identifier sent from the user&#39;s terminal which reads the advertisement identifier from the radio tag when the tag information for the radio tag is displayed, the radio tag to which the advertisement identifier issued in the advertisement-identifier issuing step has been written by the radio-tag management device. 
     According to still another aspect of the present invention, a device for managing advertisement includes an issuing unit that issues an advertisement identifier for identifying an advertisement in response to a request from a radio-tag management device which manages information on a radio tag, the advertisement being displayed in addition to tag information when a user&#39;s terminal displays the tag information, the user&#39;s terminal being used by a purchaser of an item attached with a radio tag; and a transmitting unit that transmits an advertisement in response to a transmission request of the advertisement corresponding to the advertisement identifier sent from the user&#39;s terminal which reads the advertisement identifier from the radio tag when the tag information for the radio tag is displayed, the radio tag to which the advertisement identifier issued in the advertisement-identifier issuing step has been written by the radio-tag management device. 
     According to still another aspect of the present invention, an apparatus for managing a user&#39;s terminal includes a reading unit that reads an advertisement identifier for identifying an advertisement related to an item attached with a radio tag, from the radio tag; a requesting unit that requests transmission of an advertisement to an advertisement management device which manages the advertisement associated with the advertisement identifier corresponding to read advertisement identifier; and a displaying unit that displays an advertisement received from the advertisement management device along with tag information. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic for explaining the method of preventing leakage of traceability information in a radio-tag system according to an embodiment of the present invention; 
         FIG. 2  is a detailed functional block diagram the radio-tag system shown in  FIG. 1 ; 
         FIG. 3  depicts an example of the contents of an advertisement-content table shown in  FIG. 2 ; 
         FIG. 4  depicts an example of the contents of an advertisement-ID management table shown in  FIG. 2 ; 
         FIG. 5  depicts an example of the contents of a tag-information table shown in  FIG. 2 ; 
         FIG. 6  depicts an example of the contents of an advertisement management table shown in  FIG. 2 ; 
         FIG. 7  depicts an example of display by a tag-information display unit shown in  FIG. 2 ; 
         FIG. 8  is a flowchart of the processes performed by the radio-tag system shown in  FIG. 2  when displaying traceability information; 
         FIG. 9  is a flowchart of an advertisement-ID issuing process performed by an advertisement-ID issuing unit shown in  FIG. 2 ; 
         FIG. 10  is a flowchart of an advertisement-information providing process performed by an advertisement-use management unit shown in  FIG. 2 ; 
         FIG. 11  is a flowchart of an advertisement-ID-issue requesting process performed by an advertisement-ID-issue requesting unit shown in  FIG. 2 ; 
         FIG. 12  is a flowchart of an advertisement-ID writing process performed by the advertisement-ID writing unit shown in  FIG. 2 ; 
         FIG. 13  is a flowchart of a tag-information informing process performed by a tag-information informing unit shown in  FIG. 2 ; 
         FIG. 14  is a flowchart of a tag-information displaying process performed by a tag-information display unit shown in  FIG. 2 ; 
         FIG. 15  is a functional block diagram of a computer that realizes the units, steps, process, methods according to the embodiment; and 
         FIG. 16  is a schematic for explaining the problems in the conventional technology. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of the present invention are explained in detail below with reference to the attached drawings. Embodiments of the present invention are explained below by taking a food product as an example of an item; however, the embodiments can be similarly applied to any other product. 
       FIG. 1  is a schematic for explaining the method of preventing leakage of traceability information in a radio-tag system  1  according to an embodiment. 
     The radio-tag system  1  includes a radio-tag management device  200 , an advertisement management device  100 , and a user terminal  300 . The radio-tag management device  200  requests issue of an advertisement ID for identifying an advertisement related to an item to be attached with a radio tag, to an advertisement management device  100  (see (1) if  FIG. 1 ), and the advertisement management device  100  issues the advertisement ID (see (2)). 
     The radio-tag management device  200  manages the advertisement ID, issued by the advertisement management device  100 , associated with the tag ID, and writes the advertisement ID to the radio tag when space becomes available in a storage area of the radio tag (see (3)). Therefore, for example, when a radio tag is in a production stage, the radio tag stores therein its own tag ID, tag information A, and advertisement ID. 
     The advertisement management device  100  manages the advertisement ID and advertisement information is associated manner. The user&#39;s terminal  300  is generally possessed by a customer and includes a tag reader that can read information in a radio tag. Assume that a consumer becomes interested in an item and operates the user&#39;s terminal  300  and reads information present in the radio tag attached to the item. In this case, the user&#39;s terminal  300  reads a tag ID, tag information A, and advertisement ID from the radio tag, sends the tag ID to the radio-tag management device  200  and requests the radio-tag management device  200  to send traceability information corresponding to the tag ID in return, sends the advertisement ID to the advertisement management device  100  and requests the advertisement management device  100  to send advertisement information corresponding to the advertisement ID in return (see (4)). 
     As a result, the radio-tag management device  200  transmits the traceability information to the user&#39;s terminal  300  and the advertisement management device  100  transmits the advertisement information to the user&#39;s terminal  300  (see (5)). The user&#39;s terminal  300  displays the traceability information together with the advertisement information. 
     As described above, in the radio-tag system  1 , the advertisement management device  100  manages the advertisement ID associated with the advertisement information, instead of management of the tag ID associated with the advertisement information. Therefore, because the advertisement management device  100  does not manage tag IDs, the possibility of leakage of traceability information can be eliminated. 
       FIG. 2  is a detailed functional block diagram of the radio-tag system  1 . The radio-tag system  1  includes the advertisement management device  100 , the radio-tag management device  200 , and the user&#39;s terminal  300  connected to one another through the Internet  40 . 
     For convenience in explanation, only one unit of the advertisement management device  100  and one unit of the user&#39;s terminal  300  are shown here, but the radio-tag system  1  can include a plurality of advertisement management devices  100  and a plurality of user&#39;s terminals  300 . 
     The advertisement management device  100  is a device that manages advertisements, and includes an advertisement-information storage unit  110 , an advertisement-information register unit  120 , an advertisement-ID issuing unit  130 , an advertisement-use management unit  140 , and an advertisement totaling unit  150 . 
     The advertisement-information storage unit  110  is a storage unit that stores information for managing advertisements, and includes an advertisement-content table  111  and an advertisement-ID management table  112 . 
     The advertisement-content table  111  is a table that stores information on advertisements.  FIG. 3  depicts an example of the contents of the advertisement-content table  111 . The advertisement-content table  111  stores therein data associated with one another, for each advertisement, such as a register ID for identifying an advertisement used in the radio-tag system  1 , an advertisement type indicating a type of an advertisement corresponding to a type of an item to be attached with a radio tag, advertisement information, advertiser information indicating a name of an advertiser and its contact information, a contract condition indicating a calculation condition for a price for advertisement to be paid by an advertiser, and an issued advertisement ID which is an advertisement ID issued to the radio-tag management device  200 . 
     The advertisement-ID management table  112  is a table that stores information for advertisement IDs issued to the radio-tag management device  200 .  FIG. 4  depicts an example of the contents of the advertisement-ID management table  112 . The advertisement-ID management table  112  stores therein data associated with one another, for each advertisement ID issued, such as an advertisement ID, a register ID of a target advertisement, an address of a radio-tag management device to which the advertisement ID is issued, and the number of accesses being the number of access times each in which the advertisement information is accessed by using the advertisement ID. 
     The advertisement-information register unit  120  is a processor that accepts information on an advertisement from an advertiser and stores it in the advertisement-information storage unit  110 . More specifically, the advertisement-information register unit  120  registers information such as advertisement types, the advertisement information, the advertiser information, and the contract condition in the advertisement-content table  111 . 
     The advertisement-ID issuing unit  130  is a processor that accepts an advertisement-ID-issue request from the radio-tag management device  200  and issues an advertisement ID. More specifically, the advertisement-ID issuing unit  130  searches the advertisement-content table  111  to identify an advertisement of which advertisement type matches an item type specified by the radio-tag management device  200 , creates an advertisement ID for the advertisement identified, and issues the advertisement ID. 
     Furthermore, the advertisement-ID issuing unit  130  registers the advertisement ID issued in the advertisement-content table  111  as an issued advertisement ID, creates a new entry in the advertisement-ID management table  112 , and registers the advertisement ID issued, the register ID, and the address of the radio-tag management device. 
     The advertisement-use management unit  140  is a processor that transmits advertisement information in response to an advertisement-information transmission request from the user&#39;s terminal  300 . More specifically, the advertisement-use management unit  140  searches the advertisement-ID management table  112  to obtain a register ID corresponding to an advertisement ID specified by the user&#39;s terminal  300 , searches the advertisement-content table  111  using the register ID obtained to obtain advertisement information, and transmits the advertisement information to the user&#39;s terminal  300 . Furthermore, the advertisement-use management unit  140  increments the number of accesses related to the advertisement ID in the advertisement-ID management table  112  by “1”, the advertisement ID being specified through the user&#39;s terminal  300 . 
     The advertisement totaling unit  150  is a processor that calculates a price for advertisement which an advertiser pays to a purchaser of the radio tag based on the number of accesses in the advertisement-ID management table  112  and the contract condition in the advertisement-content table  111  when the use of the advertisement ID is complete, and that informs the price to the advertiser and the radio-tag management device  200 . Furthermore, the advertisement totaling unit  150  receives the result of comparison between the price of advertisement calculated by its own and the price of advertisement calculated by the radio-tag management device  200 , from the radio-tag management device  200 , and transmits the result to the advertiser. 
     The radio-tag management device  200  is a device that manages information on radio tags, and includes a tag-information storage unit  210 , a tag-information register unit  220 , an advertisement-ID-issue requesting unit  230 , an advertisement-ID writing unit  240 , a tag-information informing unit  250 , and an advertisement-revenue calculating unit  260 . 
     The tag-information storage unit  210  is a storage unit that stores information for managing radio tags, and includes a tag information table  211  and an advertisement management table  212 . 
     The tag information table  211  is a table that stores information on radio tags.  FIG. 5  depicts an example of the contents of the tag information table  211 . The tag information table  211  stores data associated with one another, for each radio tag, such as a tag ID, a purchaser information indicating a name of a purchaser of a radio tag and its contact information, tag information containing traceability information, and an advertisement ID for connecting a radio tag to an advertisement related to an item to be attached with the radio tag. 
     The advertisement management table  212  is a table that stores information on advertisements each related to an item to be attached with a radio tag.  FIG. 6  depicts an example of the contents of the advertisement management table  212 . The advertisement management table  212  stores therein, for each advertisement ID issued by the advertisement management device  100 , an item type indicating a type of an item to be attached with a radio tag, an address of an advertisement management device indicating the address of the advertisement management device  100  which issues the advertisement ID, an advertisement ID, the number of accesses indicating the number of times at which a consumer views traceability information stored in the radio tag, a contract condition, and the charges due to advertisements collected. It is assumed that an item type and an address of an advertisement management device which manages an advertisement related to the item type are previously registered in the advertisement management table  212 . 
     The tag-information register unit  220  is a processor that registers information stored in the tag-information storage unit  210 . More specifically, the tag-information register unit  220  registers the purchaser information and the tag information in the tag information table  211 , and registers the item type and the address of the advertisement management device in the advertisement management table  212 . 
     The advertisement-ID-issue requesting unit  230  is a processor that specifies a type of an item to be attached with a radio tag to request issue of an advertisement ID to the advertisement management device  100 . The processor receives the advertisement ID issued and the contract condition for a corresponding advertisement from the advertisement management device  100 , stores the advertisement ID associated with the tag ID in the tag information table  211 , and stores the advertisement ID and the contract condition, which are associated with the item type, in the advertisement management table  212 . 
     The advertisement-ID-issue requesting unit  230  requests the advertisement ID to the advertisement management device  100 , stores the advertisement ID issued associated with the tag ID in the tag information table  211 , and stores the advertisement ID and the contract condition, which are associated with the item type, in the advertisement management table  212 , and this allows the radio-tag management device  200  to manage information on the advertisement associated with the radio tag. The advertisement-ID-issue requesting unit  230  identifies an address of the advertisement management device  100  to which the advertisement ID is requested, using the advertisement management table  212 . 
     The advertisement-ID writing unit  240  is a processor that searches the advertisement management table  212  to find an advertisement ID corresponding to an item to be attached with a radio tag, and writes the advertisement ID to the radio tag when space becomes available in the storage area of the radio tag. 
     The advertisement-ID writing unit  240  searches the advertisement management table  212  to find an advertisement ID corresponding to an item to be attached with a radio tag and writes the advertisement ID to the radio tag, and the user&#39;s terminal  300  can thereby read the advertisement ID from the radio tag and request the corresponding advertisement information to the advertisement management device  100 . 
     The tag-information informing unit  250  is a processor that transmits traceability information in response to the request from the user&#39;s terminal  300 . More specifically, the tag-information informing unit  250  receives the tag ID from the user&#39;s terminal  300 , searches the tag information table  211  using the tag ID to fetch tag information, extracts traceability information from the tag information, and transmits the traceability information to the user&#39;s terminal  300 . 
     Furthermore, the tag-information informing unit  250  searches the tag information table  211  using the tag ID to obtain a corresponding advertisement ID, searches the advertisement management table  212  using the advertisement ID obtained to obtain an address of the advertisement management device, and transmits the address to the user&#39;s terminal  300 , and at the same time, increments the number of accesses in the advertisement management table  212  by “1”. 
     The advertisement-revenue calculating unit  260  is a processor that calculates a price for advertisement which an advertiser pays to a radio-tag purchaser based on the number of accesses and the contract condition in the advertisement management table  212  upon completion of the use of the advertisement ID, and that stores the price as charges to be collected, in the advertisement management table  212 . The advertisement-revenue calculating unit  260  receives the price for advertisement calculated by the advertisement management device  100 , compares the price with the price calculated by its own, and transmits the result of comparison to the radio-tag purchaser and the advertisement management device  100 . 
     The user&#39;s terminal  300  is a device used when a consumer who purchases an item attached with the radio tag views its traceability information, and includes a tag reader and a tag-information display unit  310 . 
     The tag-information display unit  310  is a processor that acquires traceability information and an address of an advertisement management device from the radio-tag management device  200  using the tag ID read from the radio tag by the tag reader, acquires advertisement information from the advertisement management device  100  of the address of the advertisement management device acquired, and displays the traceability information together with the advertisement. 
       FIG. 7  depicts an example of display of the traceability information and the advertisement on the tag-information display unit  310 . Assuming an item is cabbage, the tag-information display unit  310  displays a recipe for a cabbage dish and copy of advertisement for source for Hoi-Ko-Ro of A Foods as an advertisement, in addition to the traceability information. 
     The overview of processes up to display of the traceability information by the radio-tag system  1  according to the embodiment is explained below.  FIG. 8  is a flowchart of the overview of processes up to display of the traceability information by the radio-tag system  1 . 
     As shown in  FIG. 8 , in the radio-tag system  1 , when the advertisement-ID-issue requesting unit  230  of the radio-tag management device  200  requests issue of an advertisement ID to the advertisement management device  100  (step S 101 ), the advertisement-ID issuing unit  130  of the advertisement management device  100  creates an advertisement ID, and transmits the advertisement ID created to the radio-tag management device  200  (step S 102 ). 
     Then, the advertisement-ID-issue requesting unit  230  registers the advertisement ID or so received, in the tag information table  211  and the advertisement management table  212  (step S 103 ). Then, when space becomes available in the storage area of the radio tag, the advertisement-ID writing unit  240  writes the advertisement ID corresponding to the radio tag to the radio tag (step S 104 ). In parallel with the processes at step S 101  to step S 104 , the traceability information is stored in the radio-tag management device  200 . 
     Thereafter, when the consumer purchases an item attached with the radio tag and operates the user&#39;s terminal  300  for viewing its traceability information, the tag-information display unit  310  of the user&#39;s terminal  300  requests the traceability information to the radio-tag management device  200  (step S 105 ). After the step, the tag-information informing unit  250  of the radio-tag management device  200  transmits the traceability information and the address of the advertisement management device (step S 106 ), and the tag-information display unit  310  requests the advertisement information to the advertisement management device  100  using the address of the advertisement management device (step S 107 ). 
     Then, the advertisement-use management unit  140  of the advertisement management device  100  transmits the advertisement information to the user&#39;s terminal  300  (step S 108 ), and the tag-information display unit  310  receives the advertisement information and displays the advertisement together with the traceability information (step S 109 ). 
     By displaying the advertisement using the advertisement ID in the above manner, the advertisement management device  100  does not need to store the tag ID. This allows elimination of the risk of leakage of traceability information, which is the personal information, from the advertisement management device  100  caused by the access of the advertisement management device  100  to the traceability information. 
     Procedures for the advertisement management device  100 , the radio-tag management device  200 , and the user&#39;s terminal  300  are explained below with reference to  FIG. 9  to  FIG. 14 .  FIG. 9  is a flowchart of an advertisement-ID issuing process performed by the advertisement-ID issuing unit  130 . 
     As shown in  FIG. 9 , in the advertisement-ID issuing process, the advertisement-ID issuing unit  130  receives an advertisement-ID-issue request with a specified item type from the radio-tag management device  200  (step S 201 ), and searches the advertisement-content table  111  based on the item type to identify the register ID and contract condition corresponding to the item (step S 202 ). 
     The advertisement-ID issuing unit  130  creates an advertisement ID and registers it as an issued advertisement ID in the advertisement-content table  111 , and registers the advertisement ID created, the register ID, and the address of the radio-tag management device  200  that requests the advertisement ID, as a new entry, in the advertisement-ID management table  112  (step S 203 ). And the advertisement-ID issuing unit  130  transmits the advertisement ID created together with the contract condition to the radio-tag management device  200  (step S 204 ). 
     In this manner, the advertisement-ID issuing unit  130  creates the advertisement ID corresponding to the item type specified by the radio-tag management device  200 , registers the advertisement ID created in the advertisement-content table  111  and the advertisement-ID management table  112 , and transmits the advertisement ID to the radio-tag management device  200 , to thereby enable management of the advertisement using the advertisement ID. 
       FIG. 10  is a flowchart of an advertisement-information providing process performed by the advertisement-use management unit  140 . In the advertisement-information providing process, the advertisement-use management unit  140  receives an advertisement-information transmission request together with the advertisement ID from the user&#39;s terminal  300  (step S 301 ). 
     Then, the advertisement-use management unit  140  searches the advertisement-ID management table  112  using the advertisement ID to identify the register ID of the advertisement information (step S 302 ), and increments the number of accesses in the advertisement-ID management table  112  by “1”. 
     Further, the advertisement-use management unit  140  searches the advertisement-content table  111  using the register ID identified to obtain the advertisement information (step S 303 ), and transmits the advertisement information obtained to the user&#39;s terminal  300  (step S 304 ). 
     In this manner, the advertisement-use management unit  140  receives the advertisement ID from the user&#39;s terminal  300  and transmits the corresponding advertisement information to the user&#39;s terminal  300 , and the user&#39;s terminal  300  can thereby display the advertisement together with the traceability information. 
       FIG. 11  is a flowchart of an advertisement-ID-issue requesting process performed by the advertisement-ID-issue requesting unit  230 . In the advertisement-ID-issue requesting process, the advertisement-ID-issue requesting unit  230  specifies the type of an item to be attached with a radio tag and requests issue of an advertisement ID to the advertisement management device  100  (step S 401 ). 
     The advertisement-ID-issue requesting unit  230  receives the advertisement ID and its contract condition from the advertisement management device  100  (step S 402 ), and registers the advertisement ID and its contract condition corresponding to the item type in the advertisement management table  212  (step S 403 ). 
     In this manner, the advertisement-ID-issue requesting unit  230  requests issue of the advertisement ID to the advertisement management device  100  and registers the advertisement ID issued in a predetermined location of the advertisement management table  212 , and the radio-tag management device  200  can thereby manage the item type associated with the advertisement ID. 
       FIG. 12  is a flowchart of an advertisement-ID writing process performed by the advertisement-ID writing unit  240 . The advertisement-ID writing process is started when space becomes available in the storage area of the radio tag. 
     As shown in  FIG. 12 , in the advertisement-ID writing process, the advertisement-ID writing unit  240  searches the advertisement management table  212  using the type of an item to be attached with a radio tag to obtain an advertisement ID (step S 501 ). 
     Then, the advertisement-ID writing unit  240  writes the advertisement ID obtained to the radio tag (step S 502 ), and registers the advertisement ID associated with the radio tag, to which the advertisement ID has been written, in the tag information table  211  (step S 503 ). 
     In this manner, the advertisement-ID writing unit  240  writes the advertisement ID to the radio tag and registers the advertisement ID in a corresponding location of the tag information table  211 , and the radio-tag management device  200  can thereby manage the radio tag associated with the advertisement ID. 
       FIG. 13  is a flowchart of a tag-information informing process performed by the tag-information informing unit  250 . In the tag-information informing process, the tag-information informing unit  250  receives a tag ID and a tag-information transmission request from the user&#39;s terminal  300  (step S 601 ). 
     Then, the tag-information informing unit  250  searches the tag information table  211  using the tag ID to obtain tag information and an advertisement ID, and extracts traceability information from the tag information obtained (step S 602 ). Furthermore, the tag-information informing unit  250  searches the advertisement management table  212  using the advertisement ID obtained to obtain an address of an advertisement management device and increments the number of accesses by “1” (step S 603 ). Then, the tag-information informing unit  250  transmits the traceability information and the address of the advertisement management device to the user&#39;s terminal  300  (step S 604 ). 
     In this manner, the tag-information informing unit  250  transmits the traceability information and the address of the advertisement management device corresponding to the tag ID, to the user&#39;s terminal  300 , and the user&#39;s terminal  300  can identify the advertisement management device  100  to which transmission of the advertisement information is requested, based on the advertisement ID read from the radio tag. 
       FIG. 14  is a flowchart of a tag-information displaying process performed by the tag-information display unit  310 . In the tag-information displaying process, the tag-information display unit  310  reads the tag ID and the advertisement ID (step S 701 ). 
     Then, the tag-information display unit  310  transmits the tag ID to the radio-tag management device  200 , and requests the traceability information and the address of the advertisement management device (step S 702 ). When receiving the traceability information and the address of the advertisement management device (step S 703 ), the tag-information display unit  310  transmits the advertisement ID to the advertisement management device  100  of the address received, and requests the advertisement information (step S 704 ). When receiving the advertisement information, the tag-information display unit  310  displays the advertisement together with the traceability information (step S 705 ). 
     In this manner, the tag-information display unit  310  acquires the traceability information from the radio-tag management device  200  and acquires the advertisement information from the advertisement management device  100 , which allows the advertisement in addition to the traceability information to be displayed on the user&#39;s terminal  300 . 
     As explained above, in the embodiment, the advertisement-ID-issue requesting unit  230  of the radio-tag management device  200  requests issue of the advertisement ID to the advertisement management device  100 , the advertisement-ID issuing unit  130  of the advertisement management device  100  issues the advertisement ID. When space becomes available in the storage area of the radio tag, the advertisement-ID writing unit  240  writes the advertisement ID to the radio tag. When the consumer who purchases an item attached with the radio tag operates the user&#39;s terminal  300  to view the traceability information for the item, the tag-information display unit  310  of the user&#39;s terminal  300  reads a tag ID and an advertisement ID from the radio tag, specifies the tag ID to acquire the traceability information from the radio-tag management device  200 , specifies the advertisement ID to acquire the advertisement information from the advertisement management device  100 , and displays the advertisement in addition to the traceability information. This allows the advertisement management device  100  to manage advertisements without using each tag ID. 
     Therefore, the advertisement management device  100  cannot acquire the traceability information from the radio-tag management device  200  using the tag ID. As a result, it is possible to eliminate the risk of traceability information leaking from the advertisement management device  100 . 
     In the embodiment, the case where a plurality of advertisement management devices  100  are provided is explained, but the advertisement management device  100  may be provided as a single unit. When there is one advertisement management device  100 , the user&#39;s terminal  300  can access the advertisement management device  100  of a fixed address without acquiring the address of an advertisement management device from the radio-tag management device  200 , and acquire advertisement information. 
     In the embodiment, the case where the radio-tag management device  200  is provided as a single unit is explained, but a plurality of radio-tag management devices  200  can be provided. However, when the plurality of the radio-tag management devices  200  are to be provided, a device is required. The device manages a correlation between tag IDs and the radio-tag management devices  200  so that the user&#39;s terminal  300  can query the correlation using the tag ID to identify a radio-tag management device  200  which should be accessed. 
     In the embodiment, the case where the purchaser of a radio tag uses the radio tag is explained, but the present invention is also applicable to a case, in addition to the above case, in which the purchaser of the radio tag permits another radio-tag user to use a part of a storage area in the radio tag or to use it in a fixed period, and in which the radio-tag user permitted to use the radio tag is to obtain advertisement revenue. 
     In the embodiment, the case where the advertisement ID is written to the radio tag and the user&#39;s terminal  300  reads the advertisement ID from the radio tag for use is explained. However, only a tag ID is written to the radio tag, and the user&#39;s terminal  300  can query the radio-tag management device  200  using the tag ID read from the radio tag to identify the advertisement ID. 
     In the embodiment, the advertisement management device, the radio-tag management device, and the user&#39;s terminal are explained, but the configurations of these devices are implemented by software to obtain an advertisement management program, a radio-tag management program, and a user program, respectively, each of which has the same function as above. As one of examples, a computer that executes the radio-tag management program is explained below. 
       FIG. 15  is a functional block diagram of a computer  400  that executes the radio-tag management program according to the embodiment. The computer  400  includes a random access memory (RAM)  410 , a central processing unit (CPU)  420 , a hard disk drive (HDD)  430 , a local area network (LAN) interface  440 , an input/output interface  450 , and a digital versatile disk (DVD) drive  460 . 
     The RAM  410  is a memory that stores a program and a result in the middle of execution of the program or the like, and the CPU  420  is the central processing unit that reads the program from the RAM  410  and executes it. 
     The HDD  430  is a disk device that stores programs and data, and the LAN interface  440  is an interface for connecting the computer  400  to another computer through LAN. 
     The input/output interface  450  is an interface for connecting an input device such as a mouse and a keyboard and a display unit to the computer  400 , and the DVD drive  460  is a device that performs read/write on DVD. 
     A radio-tag management program  411  executed in the computer  400  is stored in DVD, is read from the DVD by the DVD drive  460 , and is installed in the computer  400 . 
     Alternatively, the radio-tag management program  411  is stored in a database of another computer system connected through the LAN interface  440 , is read from the database, and installed in the computer  400 . 
     The radio-tag management program  411  installed is stored in the HDD  430 , is read to the RAM  410 , and is executed as a radio-tag management process  421  by the CPU  420 . 
     According to an aspect of the present invention, an advertisement management device manages advertisement and advertisement IDs, a radio-tag management device manages tag IDs and traceability information, and a user terminal manages sends an advertisement ID to the advertisement management device to fetch an advertisement and sends tag ID to the radio-tag management device to fetch traceability information from the radio-tag management device. Therefore, even if a person has access to the advertisement management device he cannot acquire tag IDs from the radio-tag management device so that he cannot acquire traceability information. 
     According to another aspect, advertisement revenue is accurately calculated, and this allows a tag purchaser to charge an advertiser for an appropriate advertisement price. 
     According to still another aspect, an appropriate advertisement is displayed together with the tag information, and this allows a highly effective advertisement to be displayed. 
     Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.